Displaying publications 1 - 20 of 65 in total

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  1. Recent advances in green solvents for lignocellulosic biomass pretreatment: Potential of choline chloride (ChCl) based solvents
    Yiin CL, Yap KL, Ku AZE, Chin BLF, Lock SSM, Cheah KW, et al.
    Bioresour Technol, 2021 Aug;333:125195.
    PMID: 33932810 DOI: 10.1016/j.biortech.2021.125195
    Biomass wastes exhibit a great potential to be used as a source of non-depleting renewable energy and synthesis of value-added products. The key to the valorization of excess lignocellulosic biomass wastes in the world lies on the pretreatment process to recalcitrant barrier of the lignocellulosic material for the access to useful substrates. A wide range of pretreatment techniques are available and advances in this field is continuously happening, in search for cheap, effective, and environmentally friendly methods. This review starts with an introduction to conventional approaches and green solvents for pretreatment of lignocellulosic biomass. Subsequently, the mechanism of actions along with the advantages and disadvantages of pretreatment techniques were reviewed. The roles of choline chloride (ChCl) in green solvents and their potential applications were also comprehensively reviewed. The collection of ideas in this review serve as an insight for future works or interest on biomass-to-energy conversion using green solvents.
    Matched MeSH terms: Choline*
  2. Simulation of Deep Eutectic Solvents' Interaction with Membranes of Cancer Cells Using COSMO-RS
    Mbous YP, Hayyan M, Wong WF, Hayyan A, Looi CY, Hashim MA
    J Phys Chem B, 2020 10 15;124(41):9086-9094.
    PMID: 32930594 DOI: 10.1021/acs.jpcb.0c04801
    Deep eutectic solvent (DES) affinities with cellular membranes structures dictate the degree of cytotoxicity that results from these interactions. The physicochemical properties of choline chloride (ChCl)-DESs suggest non-negligible cytotoxicities that were attested by published researches. In this study, the profiles of novel N,N-diethylammonium chloride (DAC)-based-deep eutectic solvents (DESs) prepared with various hydrogen bond donors (urea, glycerol, ethylene glycol, malonic acid, and zinc chloride) were compared to those of ChCl-DESs by using HelaS3, AGS, MCF-7, and WRL-68 cancer cell lines. The molecular interactions between salts and cellular membranes were investigated to explain the observed cytotoxicity. The results show that ChCl-based DESs (279 ≤ IC50 ≥ 1260 mM) were less toxic than DAC-based DESs (37 ≤ IC50 ≥ 109 mM). COSMO-RS analysis emphasized the importance of salt hydrophobicity with regards to DESs cytotoxicity. Malonic acid increased hydrophobicity and cytotoxicity in general, thus highlighting the potential of ammonium salt-based DESs as anticancer agents.
    Matched MeSH terms: Choline*
  3. Sequential pretreatment with alkaline hydrogen peroxide and choline chloride:copper (II) chloride dihydrate - Synergistic fractionation of oil palm fronds
    Ho MC, Wu TY
    Bioresour Technol, 2020 Apr;301:122684.
    PMID: 31954964 DOI: 10.1016/j.biortech.2019.122684
    In this study, a novel Type II deep eutectic solvent (DES) namely, choline chloride:copper(II) chloride dihydrate (ChCl:CuCl2·2H2O) was used to pretreat oil palm fronds (OPFs). The sequential pretreatment with alkaline hydrogen peroxide (0.25 vol%, 90 min) at ambient conditions and a Type II DES (90 °C, 3 h) at a later stage resulted in a delignification of 55.14% with high xylan (80.79%) and arabinan (98.02%) removals. The characterizations of pretreated OPFs confirmed the excellent performance of DES in OPF fractionation. Thus, the application of a Type II DES at ambient pressure and relatively lower temperature was able to improve the lignin and hemicellulose removals from OPFs.
    Matched MeSH terms: Choline*
  4. Physicochemical and thermal characteristics of choline chloride-based deep eutectic solvents
    Sazali AL, AlMasoud N, Amran SK, Alomar TS, Pa'ee KF, El-Bahy ZM, et al.
    Chemosphere, 2023 Oct;338:139485.
    PMID: 37442394 DOI: 10.1016/j.chemosphere.2023.139485
    It is essential to investigate the physicochemical and thermal properties of choline chloride (ChCl)-based deep eutectic solvents (DESs) as hydrogen bond acceptor (HBA) with various hydrogen bond donor (HBD) functional groups, such as α-hydroxy acid (lactic acid) or polyol (glycerol). It is important to consider how molar ratios impact these properties, as they may be altered for particular applications. This study aimed to examine the physicochemical and thermal properties of ChCl-based DESs with lactic acid (LA) or glycerol (Gly) at different molar ratios (1:2-1:10). The pH of ChCl:LA (0-1.0) is lower than that of ChCl:Gly (4.0-5.0) because of the hydrogen bonds between ChCl and LA. A higher amount of LA/Gly resulted in higher densities of ChCl:Gly (1.20-1.22 g cm-3) and ChCl:LA (1.16-1.19 g cm-3) due to the stronger hydrogen bonds and tighter packing of the molecules. The refractive index of ChCl:Gly (1.47-1.48) was higher than ChCl:LA (1.44-1.46), with a trend similar to density. The viscosities of ChCl:Gly (0.235-0.453 Pa s) and ChCl:LA (0.04-0.06 Pa s) increased with increasing LA/Gly molar ratio but decreased with temperature due to the high kinetic energy from heating, lowering the attractive forces between molecules. The activation energy for ChCl:LA (15.29-15.55 kJ mol-1) is greater than for ChCl:Gly (7.77-8.78 kJ mol-1), indicating that ChCl:LA has a greater viscosity-temperature dependence than ChCl:Gly. The DESs decomposition temperatures are 179.73-192.14 °C for ChCl:LA and 189.69-197.41 °C for ChCl:Gly. Freezing temperatures are correlated with the molecular weight of HBDs, with lower values causing a larger decrease in freezing temperatures. The interactions of polyols with anions were stronger than those of α-hydroxy acids with anions. The variations in HBA to HBD molar ratios affected DESs properties, providing a fundamental understanding of the properties critical for their diverse applications.
    Matched MeSH terms: Choline/chemistry
  5. Ionic liquid-based dispersive liquid-liquid microextraction of succinic acid from aqueous streams: COSMO-RS screening and experimental verification
    Khan HW, Zailan AA, Bhaskar Reddy AV, Goto M, Moniruzzaman M
    Environ Technol, 2024 Aug;45(19):3828-3839.
    PMID: 37415504 DOI: 10.1080/09593330.2023.2234669
    In the present investigation, a total of 108 combinations of ionic liquids (ILs) were screened using the conductor-like screening model for real solvents (COSMO-RS) with the aid of six cations and eighteen anions for the extraction of succinic acid (SA) from aqueous streams through dispersive liquid-liquid microextraction (DLLME). Using the screened ILs, an ionic liquid-based DLLME (IL-DLLME) was developed to extract SA and the role of different reaction parameters in the effectiveness of IL-DLLME approach was investigated. COSMO-RS results suggested that, quaternary ammonium and choline cations form effective IL combinations with [OH¯], [F¯], and [SO42¯] anions due to hydrogen bonding. In view of these results, one of the screened ILs, tetramethylammonium hydroxide [TMAm][OH] was chosen as the extractant in IL-DLLME process and acetonitrile was adopted as the dispersive solvent. The highest SA removal efficiency of 97.8% was achieved using 25 μL of IL [TMAm][OH] as a carrier and 500 μL of acetonitrile as dispersive solvent. The highest amount of SA was extracted with a stir time of 20 min at 300 rpm, followed by centrifugation for 5 min at 4500 rpm. Overall, the findings showed that IL-DLLME is efficient in extracting succinic acid from aqueous environments while adhering to the first-order kinetics.
    Matched MeSH terms: Choline/analogs & derivatives; Choline/chemistry
  6. Convenient and Efficient Method for Quality Control Analysis of 18F-Fluorocholine: For a Small Scale GMP-based Radiopharmaceuticals Laboratory Set-up
    Hassan H, Abu Bakar S, Halim KN, Idris J, Nordin AJ
    Curr Radiopharm, 2016;9(2):128-36.
    PMID: 26013570
    BACKGROUND AND OBJECTIVE: Prostate cancer continues to be the most prevalent cancer in men in Malaysia. As time progresses, the prospect of PET imaging modality in diagnosis of prostate cancer is promising, with on-going improvement on novel tracers. Among all tracers, 18F-Fluorocholine is reported to be a reputable tracer and reliable diagnostic technique for prostate imaging. Nonetheless, only 18F-Fluorodeoxyglucose (18F-FDG) is available and used in most oncology cases in Malaysia. With a small scale GMP-based radiopharmaceuticals laboratory set-up, initial efforts have been taken to put Malaysia on 18F-Fluorocholine map. This article presents a convenient, efficient and reliable method for quality control analysis of 18F-Fluorocholine. Besides, the aim of this research work is to assist local GMP radiopharmaceuticals laboratories and local authority in Malaysia for quality control analysis of 18F-Fluorocholine guideline.

    METHODS: In this study, prior to synthesis, quality control analysis method for 18F-Fluorocholine was developed and validated, by adapting the equipment set-up used in 18F-Fluorodeoxyglucose (18FFDG) routine production. Quality control on the 18F-Fluorocholine was performed by means of pH, radionuclidic identity, radio-high performance liquid chromatography equipped with ultraviolet, radio- thin layer chromatography, gas chromatography and filter integrity test.

    RESULTS: Post-synthesis; the pH of 18F-Fluorocholine was 6.42 ± 0.04, with half-life of 109.5 minutes (n = 12). The radiochemical purity was consistently higher than 99%, both in radio-high performance liquid chromatography equipped with ultraviolet (r-HPLC; SCX column, 0.25 M NaH2PO4: acetonitrile) and radio-thin layer chromatography method (r-TLC). The calculated relative retention time (RRT) in r-HPLC was 1.02, whereas the retention factor (Rf) in r-TLC was 0.64. Potential impurities from 18F-Fluorocholine synthesis such as ethanol, acetonitrile, dimethylethanolamine and dibromomethane were determined in gas chromatography. Using our parameters, (capillary column: DB-200, 30 m x 0.53 mm x 1 um) and oven temperature of 35°C (isothermal), all compounds were well resolved and eluted within 3 minutes. Level of ethanol and acetonitrile in 18F-Fluorocholine were detected below threshold limit; less than 5 mg/ml and 0.41 mg/ml respectively. Meanwhile, dimethylethanolamine and dibromomethane were undetectable.

    CONCLUSION: A convenient, efficient and reliable quality control analysis work-up procedure for 18FFluorocholine has been established and validated to comply all the release criteria. The convenient method of quality control analysis may provide a guideline to local GMP radiopharmaceutical laboratories to start producing 18F-Fluorocholine as a tracer for prostate cancer imaging.

    Matched MeSH terms: Choline/analogs & derivatives*; Choline/chemical synthesis; Choline/chemistry
  7. Microwave technique for moisture content and ph determination during pre- harvest of mango cv. Chok anan
    Noradira Suhaime, Masniza Sairi, Nur Biha Mohamed Nafis, Suriati Paiman, Tity Nazleen Mohamed, Zulkifly Abbas, et al.
    Sains Malaysiana, 2018;47:1571-1578.
    The maturity of mango is usually assessed by the determination of its moisture content (m.c.), soluble solid content (SSC)
    and pH. However, these techniques are either time consuming, tedious or destructive. In this research, we extend the
    application of the open-ended coaxial probe technique to determine m.c. and pH of Chok Anan mango from its dielectric
    properties from week 5 to week 17 after anthesis. The effects of frequency and m.c. on the values of the dielectric constant
    and loss factor were also investigated. The critical frequency separating the different polarizations was found to be
    inversely proportional to m.c. Also, in this research we proposed a new classification of fruit ripeness related to the number
    of weeks after anthesis. The actual dielectric properties, m.c., SSC and pH of Chok Anan mango were measured using
    standard methods. Relationships were established between the dielectric constant, loss factor, critical frequency, pH and
    m.c. The accuracy for the determination of m.c. and pH using the coaxial probe was within 1.7% and 3.0%, respectively.
    Matched MeSH terms: Choline Kinase
  8. Unusual metal ion cofactor requirement of Entamoeba histolytica choline and ethanolamine kinase isoforms
    Chang CH, Few LL, Lim BH, Yvonne-Tee GB, Chew AL, See Too WC
    Parasitol Res, 2023 Jul;122(7):1651-1661.
    PMID: 37202563 DOI: 10.1007/s00436-023-07869-5
    The de novo biosynthesis of phosphatidylcholine and phosphatidylethanolamine in Entamoeba histolytica is largely dependent on the CDP-choline and CDP-ethanolamine pathways. Although the first enzymes of these pathways, EhCK1 and EhCK2, have been previously characterized, their enzymatic activity was found to be low and undetectable, respectively. This study aimed to identify the unusual characteristics of these enzymes in this deadly parasite. The discovery that EhCKs prefer Mn2+ over the typical Mg2+ as a metal ion cofactor is intriguing for CK/EK family of enzymes. In the presence of Mn2+, the activity of EhCK1 increased by approximately 108-fold compared to that in Mg2+. Specifically, in Mg2+, EhCK1 exhibited a Vmax and K0.5 of 3.5 ± 0.1 U/mg and 13.9 ± 0.2 mM, respectively. However, in Mn2+, it displayed a Vmax of 149.1 ± 2.5 U/mg and a K0.5 of 9.5 ± 0.1 mM. Moreover, when Mg2+ was present at a constant concentration of 12 mM, the K0.5 value for Mn2+ was ~ 2.4-fold lower than that in Mn2+ alone, without affecting its Vmax. Although the enzyme efficiency of EhCK1 was significantly improved by about 25-fold in Mn2+, it is worth noting that its Km for choline and ATP were higher than in equimolar of Mg2+ in a previous study. In contrast, EhCK2 showed specific activity towards ethanolamine in Mn2+, exhibiting Michaelis-Menten kinetic with ethanolamine (Km = 312 ± 27 µM) and cooperativity with ATP (K0.5 = 2.1 ± 0.2 mM). Additionally, we investigated the effect of metal ions on the substrate recognition of human choline and ethanolamine kinase isoforms. Human choline kinase α2 was found to absolutely require Mg2+, while choline kinase β differentially recognized choline and ethanolamine in Mg2+ and Mn2+, respectively. Finally, mutagenesis studies revealed that EhCK1 Tyr129 was critical for Mn2+ binding, while Lys233 was essential for substrate catalysis but not metal ion binding. Overall, these findings provide insight into the unique characteristics of the EhCKs and highlight the potential for new approaches to treating amoebiasis. Amoebiasis is a challenging disease for clinicians to diagnose and treat, as many patients are asymptomatic. However, by studying the enzymes involved in the CDP-choline and CDP-ethanolamine pathways, which are crucial for de novo biosynthesis of phosphatidylcholine and phosphatidylethanolamine in Entamoeba histolytica, there is great potential to discover new therapeutic approaches to combat this disease.
    Matched MeSH terms: Choline/metabolism; Choline Kinase/metabolism; Cytidine Diphosphate Choline/metabolism; Phosphatidylcholines
  9. Fulltext Phosphorylation of Human Choline Kinase Beta by Protein Kinase A: Its Impact on Activity and Inhibition
    Chang CC, Few LL, Konrad M, See Too WC
    PLoS One, 2016;11(5):e0154702.
    PMID: 27149373 DOI: 10.1371/journal.pone.0154702
    Choline kinase beta (CKβ) is one of the CK isozymes involved in the biosynthesis of phosphatidylcholine. CKβ is important for normal mitochondrial function and muscle development as the lack of the ckβ gene in human and mice results in the development of muscular dystrophy. In contrast, CKα is implicated in tumorigenesis and has been extensively studied as an anticancer target. Phosphorylation of human CKα was found to regulate the enzyme's activity and its subcellular location. This study provides evidence for CKβ phosphorylation by protein kinase A (PKA). In vitro phosphorylation of CKβ by PKA was first detected by phosphoprotein staining, as well as by in-gel kinase assays. The phosphorylating kinase was identified as PKA by Western blotting. CKβ phosphorylation by MCF-7 cell lysate was inhibited by a PKA-specific inhibitor peptide, and the intracellular phosphorylation of CKβ was shown to be regulated by the level of cyclic adenosine monophosphate (cAMP), a PKA activator. Phosphorylation sites were located on CKβ residues serine-39 and serine-40 as determined by mass spectrometry and site-directed mutagenesis. Phosphorylation increased the catalytic efficiencies for the substrates choline and ATP about 2-fold, without affecting ethanolamine phosphorylation, and the S39D/S40D CKβ phosphorylation mimic behaved kinetically very similar. Remarkably, phosphorylation drastically increased the sensitivity of CKβ to hemicholinium-3 (HC-3) inhibition by about 30-fold. These findings suggest that CKβ, in concert with CKα, and depending on its phosphorylation status, might play a critical role as a druggable target in carcinogenesis.
    Matched MeSH terms: Choline Kinase/antagonists & inhibitors; Choline Kinase/metabolism*
  10. Effect of functional groups in acid constituent of deep eutectic solvent for extraction of reactive lignin
    Tan YT, Ngoh GC, Chua ASM
    Bioresour Technol, 2019 Jun;281:359-366.
    PMID: 30831515 DOI: 10.1016/j.biortech.2019.02.010
    In this study, acidic deep eutectic solvents (DES) synthesized from various organic carboxylic acid hydrogen bond donors were applied to lignocellulosic oil palm empty fruit bunch (EFB) pretreatment. The influence of functional group types on acid and their molar ratios with hydrogen bond acceptor on lignin extraction were evaluated. The result showed presence of hydroxyl group and short alkyl chain enhanced biomass fractionation and lignin extraction. Choline chloride:lactic acid (CC-LA) with the ratio of 1:15 and choline chloride:formic acid (CC-FA) with 1:2 ratio extracted more than 60 wt% of lignin. CC-LA DES-extracted lignin (DEEL) exhibited comparable reactivity with technical and commercial lignin based on its phenolic hydroxyl content (3.33-3.72 mmol/glignin). Also, the DES-pretreated EFB comprised of enriched glucan content after biopolymer fractionation. Both DES-pretreated EFB and DEEL can be potential feedstock for subsequent conversion processes. This study presented DES as an effective and facile pretreatment method for reactive lignin extraction.
    Matched MeSH terms: Choline/chemistry
  11. One-pot furfural production using choline chloride-dicarboxylic acid based deep eutectic solvents under mild conditions
    Lee CBTL, Wu TY, Ting CH, Tan JK, Siow LF, Cheng CK, et al.
    Bioresour Technol, 2019 Apr;278:486-489.
    PMID: 30711220 DOI: 10.1016/j.biortech.2018.12.034
    The performances of various anhydrous and aqueous choline chloride-dicarboxylic acid based deep eutectic solvents (DESs) were evaluated for furfural production from oil palm fronds without any additional catalyst. The effects of different carbon chain length dicarboxylic acids and water content in each DES on furfural production were investigated. Oil palm fronds, DES and water (0-5 ml) were mixed and reacted in an oil bath (60-300 min). Reacted oil palm fronds had the potential to be reused as cellulose-rich-valuable by-products. At 100 °C, aqueous choline chloride-oxalic acid (16.4 wt% H2O) produced the highest furfural yield of 26.34% and cellulose composition up to 72.79% in the reacted oil palm fronds. Despite operating at suitable reaction duration for dicarboxylic acid with longer carbon chain length, aqueous choline chloride-malonic acid and aqueous choline chloride-succinic acid performed poorly with furfural yield of less than 1%.
    Matched MeSH terms: Choline/chemistry*
  12. Toxicity profile of choline chloride-based deep eutectic solvents for fungi and Cyprinus carpio fish
    Juneidi I, Hayyan M, Mohd Ali O
    Environ Sci Pollut Res Int, 2016 Apr;23(8):7648-59.
    PMID: 26743645 DOI: 10.1007/s11356-015-6003-4
    An investigation on the toxicological assessment of 10 choline chloride (ChCl)-based deep eutectic solvents (DESs) towards four fungi strains and Cyprinus carpio fish was conducted. ChCl was combined with materials from different chemical groups such as alcohols, sugars, acids and others to form DESs. The study was carried out on the individual DES components, their aqueous mixture before DES formation and their formed DESs. The agar disc diffusion method was followed to investigate their toxicity on four fungi strains selected as a model of eukaryotic microorganisms (Phanerochaete chrysosporium, Aspergillus niger, Lentinus tigrinus and Candida cylindracea). Among these DESs, ChCl:ZnCl2 exhibited the highest inhibition zone diameter towards the tested fungi growth in vitro, followed by the acidic group (malonic acid and p-toluenesulfonic acid). Another study was conducted to test the acute toxicity and determine the lethal concentration at 50 % (LC50) of the same DESs on C. carpio fish. The inhibition range and LC50 of DESs were found to be different from their individual components. DESs were found to be less toxic than their mixture or individual components. The LC50 of ChCl:MADES is much higher than that of ChCl:MAMix. Moreover, the DESs acidic group showed a lower inhibition zone on fungi growth. Thus, DESs should be considered as new components with different physicochemical properties and toxicological profiles, and not merely compositions of compounds.
    Matched MeSH terms: Choline/toxicity*
  13. A review on natural based deep eutectic solvents (NADESs): fundamentals and potential applications in removing heavy metals from soil
    Lai ZY, Yiin CL, Lock SSM, Chin BLF, Zauzi NSA, Sar-Ee S
    Environ Sci Pollut Res Int, 2023 Nov;30(55):116878-116905.
    PMID: 36917382 DOI: 10.1007/s11356-023-26288-8
    Natural based deep eutectic solvent (NADES) is a promising green solvent to replace the conventional soil washing solvent due to the environmental benign properties such as low toxicity, high biodegradability, high polarity or hydrophilicity, and low cost of fabrication process. The application of NADES is intensively studied in the extraction of organic compounds or natural products from vegetations or organic matters. Conversely, the use of the solvent in removing heavy metals from soil is severely lacking. This review focuses on the potential application of NADES as a soil washing agent to remove heavy metal contaminants. Hydrophilicity is an important feature of a NADES to be used as a soil washing solvent. In this context, choline chloride is often used as hydrogen bond acceptor (HBA) whereby choline chloride based NADESs showed excellent performance in the extraction of various solutes in the past studies. The nature of NADES along with its chemistry, preparation and designing methods as well as potential applications were comprehensively reviewed. Subsequently, related studies on choline chloride-based NADES in heavy metal polluted soil remediation were also reviewed. Potential applications in removing other soil contaminants as well as the limitations of NADES were discussed based on the current advancements of soil washing and future research directions were also proposed.
    Matched MeSH terms: Choline/chemistry
  14. Enhanced activity of Candida antarctica lipase B in cholinium aminoate ionic liquids: a combined experimental and computational analysis
    Chan KK, Sundaram V, Tan J, Ho YK, Ramanan RN, Ooi CW
    J Biomol Struct Dyn, 2024;42(21):11351-11365.
    PMID: 37787564 DOI: 10.1080/07391102.2023.2262590
    As a class of ionic liquids with higher biocompatibility, cholinium aminoates ([Cho][AA]) hold potential as solvation media for enzymatic bioprocessing. Herein, solvation effect of [Cho][AA] on structural stability and enzymatic activity of Candida antarctica lipase B (CALB) was evaluated using experimental and computational approaches. Influence of [Cho][AA] on CALB stability was investigated using amino acid anions ([AA]-) with varying hydrophobicity levels. Choline phenylalaninate ([Cho][Phe]) resulted in 109.1% and 110.4% of relative CALB activity to buffer medium at 25 °C and 50 °C, respectively. Simulation results revealed the improvement of CALB's enzymatic activities by [AA]- with a strong hydrophobic character. Shielding of CALB from water molecules by [AA]- was observed. The level of CALB activity was governed by accumulation level of [AA]- at CALB's first hydration layer. The stronger interaction between His224 and Asp187 was postulated to be driven by [Cho][AA], resulting in the activity enhancement of CALB. The slight improvement of CALB activity in 0.05 M [Cho][Phe] at 50 °C could be due to the larger size of entrance to the catalytic site and the stronger interaction between the catalytic residues. The promising effect of [Cho][Phe] on CALB activation may stimulate research efforts in designing a 'fully green' bioreaction for various industrial applications.Communicated by Ramaswamy H. Sarma.
    Matched MeSH terms: Choline/chemistry
  15. Investigation of laccase activity in cholinium-based ionic liquids using experimental and molecular dynamics techniques
    Chan KK, Pereira AF, Valente AI, Tavares APM, Coutinho JAP, Ooi CW
    Int J Biol Macromol, 2024 Oct;277(Pt 4):134443.
    PMID: 39217672 DOI: 10.1016/j.ijbiomac.2024.134443
    Laccases hold great potential for biotechnological applications, particularly in environmental pollutant remediation. Laccase activity is governed by the solvent environment, and ionic liquids (ILs) emerge as a versatile solvent for activation or stabilization of enzymes. Herein, effects of cholinium-based ILs formulated with carboxylic acids, inorganic acid, and amino acids as anionic species, on the catalytic activity of laccase from Trametes versicolor were investigated by experimental and computational approaches. Experimental results showed that laccase activity was enhanced by 21.39 % in 0.5 M cholinium dihydrogen citrate ([Cho][DHC]), in relation to the laccase activity in phosphate buffer medium. However, cholinium aminoate ILs negatively affected laccase activity, as evidenced by the partial deactivation of laccase in both cholinium glycinate and cholinium phenylalaninate, at concentrations of 0.1 M and 0.5 M, respectively. Molecular dynamics studies revealed that the enhancement of laccase activity in [Cho][DHC] might be attributed to the highly stabilized and compact structure of laccase, facilitating a better internal electron transfer during the laccase-substrate interactions. Enhanced catalytic performance of laccase in [Cho][DHC] was postulated to be driven by the high accumulation level of dihydrogen citrate anions around laccase's surface. [Cho][DHC] holds great promise as a cosolvent in laccase-catalyzed biochemical reactions.
    Matched MeSH terms: Choline/chemistry
  16. Fulltext Comparison between conventional and alternative peeling methods on peeling efficiencies of Malaysian ‘Chok Anan’ mango (Mangifera indica L.) fruit
    Mohamad, N.S., Sulaiman, R., Lai, O.M., Hussain, N.
    International Food Research Journal, 2017;24(5):1934-1940.
    MyJurnal
    Fruit industries require convenient peeling method, especially during puree processing to prevent deterioration of fruit quality and product loss. Therefore, manual, chemical (sodium hydroxide/NaOH) and enzymatic (Pectinex Ultra SP-L) peeling methods were compared to determine the peeling efficiencies of ‘Chok Anan’ mangoes. The effect of different peeling parameters (concentrations [chemical peeling: 1.6-7.3% of 0.4M-1.83M; enzymatic peeling: 0.005-0.095%], temperatures [chemical peeling: 80-95oC; enzymatic peeling: 25-40°C], and duration of soaking [chemical peeling: 5-10 min; enzymatic peeling: 30-120 min]) were evaluated for peeling yield, peeling time, absorption of chemical and enzyme solution, the penetration depth of NaOH and enzyme activities (reducing sugar analysis). The enzymatic peeling had significantly (p0.05) in peeling yield (>86%), but there was significant (p
    Matched MeSH terms: Choline Kinase
  17. Are deep eutectic solvents benign or toxic?
    Hayyan M, Hashim MA, Hayyan A, Al-Saadi MA, AlNashef IM, Mirghani ME, et al.
    Chemosphere, 2013 Feb;90(7):2193-5.
    PMID: 23200570 DOI: 10.1016/j.chemosphere.2012.11.004
    In continuation of investigation for environmentally benign protocol for new solvents termed deep eutectic solvents (DESs), it is herein reported results concerning the toxicity and cytotoxicity of choline chloride (ChCl) based DESs with four hydrogen bond donors including glycerine, ethylene glycol, triethylene glycol and urea. The toxicity was investigated using two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity effect was tested using the Artemia salina leach. It was found that there was no toxic effect for the tested DESs on all of the studied bacteria confirming their benign effects on these bacteria. Nevertheless, it was found that the cytotoxicity of DESs was much higher than their individual components (e.g. glycerine, ChCl) indicating that their toxicological behavior is different. For our best knowledge this is the first time that toxicity and cytotoxicity of DESs were studied. The toxicity and cytotoxicity of DESs varied depending on the structure of components. Careful usage of the terms non-toxicity and biodegradability must be considered. More investigation on this matter is required.
    Matched MeSH terms: Choline/toxicity*
  18. Fulltext DNA Methylation of Human Choline Kinase Alpha Promoter-Associated CpG Islands in MCF-7 Cells
    Mohamed Sa'dom SAF, Raikundalia S, Shamsuddin S, See Too WC, Few LL
    Genes (Basel), 2021 06 01;12(6).
    PMID: 34205960 DOI: 10.3390/genes12060853
    Choline kinase (CK) is the enzyme catalyzing the first reaction in CDP-choline pathway for the biosynthesis of phosphatidylcholine. Higher expression of the α isozyme of CK has been implicated in carcinogenesis, and inhibition or downregulation of CKα (CHKA) is a promising anticancer approach. This study aimed to investigate the regulation of CKα expression by DNA methylation of the CpG islands found on the promoter of this gene in MCF-7 cells. Four CpG islands have been predicted in the 2000 bp promoter region of ckα (chka) gene. Six CpG island deletion mutants were constructed using PCR site-directed mutagenesis method and cloned into pGL4.10 vectors for promoter activity assays. Deletion of CpG4C region located between -225 and -56 significantly increased the promoter activity by 4-fold, indicating the presence of important repressive transcription factor binding site. The promoter activity of methylated full-length promoter was significantly lower than the methylated CpG4C deletion mutant by 16-fold. The results show that DNA methylation of CpG4C promotes the binding of the transcription factor that suppresses the promoter activity. Electrophoretic mobility shift assay analysis showed that cytosine methylation at MZF1 binding site in CpG4C increased the binding of putative MZF1 in nuclear extract. In conclusion, the results suggest that DNA methylation decreased the promoter activity by promoting the binding of putative MZF1 transcription factor at CpG4C region of the ckα gene promoter.
    Matched MeSH terms: Choline Kinase/genetics*
  19. Downregulation of human choline kinase α gene expression by miR-876-5p
    Ayub Khan SM, Few LL, See Too WC
    Mol Med Rep, 2018 May;17(5):7442-7450.
    PMID: 29568919 DOI: 10.3892/mmr.2018.8762
    Choline kinase (CK) is the first enzyme in the CDP-choline pathway for the synthesis of phosphatidylcholine, the most abundant phospholipid in the mammalian cell membrane. This enzyme exists as three isozymes (α1, α2 and β) and the CKα isozyme has been implicated in cancer pathogenesis. Inhibition of CK activity has been proposed for cancer therapies. MicroRNAs (miRNAs/miRs) are non‑coding RNAs that serve important roles in diverse biological pathways and human diseases, including cancer. However, the regulation of CKα gene expression by miRNAs has never been investigated, to the best of the authors' knowledge. In the present study, two miRNA mimics, miR‑876‑5p and miR‑646, were transfected into the HepG2 cell line and the effect of these miRNAs on the levels of CKα mRNA were determined by reverse transcription‑quantitative polymerase chain reaction. Cells transfected with 25 nM miR‑876‑5p for 48 h exhibited significantly lower levels of CKα mRNA. Following optimization, miR‑876‑5p caused four times lower levels of CKα mRNA compared to the negative control. Effects of the miRNAs on HepG2 cell viability and cellular morphology were additionally analyzed using an MTT cell viability assay and scanning electron microscopy, respectively. HepG2 cells that were transfected with the optimum concentration of miR‑876‑5p for the optimum duration exhibited 25% lower viability than negative control and signs of apoptosis in electron micrographs. The results suggested miR‑876‑5p as a potential miRNA modulator of CKα expression in the cells, and may be relevant for the design of more effective anticancer strategy targeting CK.
    Matched MeSH terms: Choline Kinase/genetics*
  20. Characterization of bio-based plastic made from a mixture of Momordica charantia bioactive polysaccharide and choline chloride/glycerol based deep eutectic solvent
    Shafie MH, Samsudin D, Yusof R, Gan CY
    Int J Biol Macromol, 2018 Oct 15;118(Pt A):1183-1192.
    PMID: 29944943 DOI: 10.1016/j.ijbiomac.2018.06.103
    Momordica charantia bioactive polysaccharide (MCBP) was used as an alternative source for the production of bio-based plastics (BPs) with choline chloride/glycerol-based deep eutectic solvent (DES) as a plasticizer. In this study, MCBP was initially extracted using 0.1 M citric acid at temperature 80 °C for 2 h, precipitated using ethanol, and then lyophilized. Subsequently, seven BPs were prepared: MCBP without plasticizer (MCBP), with 1% (w/w) of glycerol (MCBP-G), or with 1% (w/w) of DES at different choline chloride/glycerol molar ratios (i.e. 1.5:1, 1:1, 1:1.5, 1:2, and 1:3). The properties of these BPs were then investigated. Results showed that the tensile strains, stresses and moduli were in the range of 1.3-13.3%, 4.8-19.1 MPa and 132-2487 MPa, respectively. The melting temperatures were found in the range of 92.6-111.4 °C whereas the moisture absorptions and water vapour transmission rates (WVTR) of BPs were 1.4-6.5% and 3.6-5.4 mg/m2·s, respectively. The results also showed that these BPs exhibited bioactivities, such as microbial inhibitory activity (19.5-32.3 mm), free radical scavenging activity (10.3-18.3%) and ferric reducing antioxidant power (FRAP, 16.1-20.0 mM). In addition, it was observed that using DES as a plasticizer had improved the properties of BP, such as tensile strain (354.7-937.5%), melting temperature (4.6-20.3%), radical scavenging activity (0.6-88.6%), FRAP (0.9-18.7%) and antimicrobial activity (12.3-33.6%) compared to MCBP, due to the fact DES has caused different degrees of plasticization via hydrogen bonds and ionic bonds with the polymer chains, and induced a lower pH condition. Therefore, it was suggested that these BPs with DES could contribute to food preservation properties.
    Matched MeSH terms: Choline/chemistry*
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