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Fulltext Effects of degree of hydrolysis on physicochemical properties of cobia (Rachycentron canadum) frame hydrolysate

Amiza, M.A., Kong, Y.L., Faazaz, A.L.

International Food Research Journal, 2012;19(1):199-206.
MyJurnal

The effect of degree of hydrolysis (DH) on the physicochemical properties of cobia frame hydrolysate was determined. Three levels of degree of hydrolysis of cobia frame hydrolysate were studied, which were 53%, 71% and 96%. After enzymatic hydrolysis using Alcalase®, the samples were spray-dried. Cobia hydrolysate powder samples were analyzed for their proximate analysis and physicochemical properties. The proximate analysis showed significant differences in fat and ash content only. DH96 hydrolysate showed desirable essential amino acid profile for human requirement except for methionine and isoleucine. The study found that cobia frame hydrolysate had good colour, emulsifying capacity and excellent foaming properties. However, there were no significant differences in water-holding capacity, oil-holding capacity and peptide solubility among the hydrolysate samples. This study suggested that cobia frame hydrolysate is a potential ingredient and foaming agent for food industry.

Matched MeSH terms: Isoleucine
Functional role of Ile264 in CYP2C8: mutations affect haem incorporation and catalytic activity

Singh R, Ting JG, Pan Y, Teh LK, Ismail R, Ong CE

Drug Metab. Pharmacokinet., 2008;23(3):165-74.
PMID: 18574320

The work described in this study aimed to express CYP2C8 wild-type and mutant proteins in bacterial expression system and to use the expressed proteins to investigate the structural and functional consequences of a reported allele CYP2C8(*)4 (carrying Ile264Met substitution) on protein activity. Ile264 was replaced by three different amino acids resulting in three mutant constructs, 2C8I264M, 2C8I264R and 2C8I264D. The presence of isoleucine at position 264 in CYP2C8 was found to be important for proper haem insertion and protein folding; whereas bulkier or charged residues were highly disruptive resulting in inactive proteins with minimum spectral and catalytic activities. This was evidenced from the low levels of Soret peak at 450 nm and negligible levels of tolbutamide methylhydroxylase activity. Kinetic study using paclitaxel indicated that all three mutants exhibited only 9.7 to 35.4% of the activity level observed in the wild-type. In addition, the mutants were more sensitive to proteinase K digestion, indicating a possible alteration of conformation. The combined effects of protein instability and compromised catalytic activity resulted in defective CYP2C8 protein which may have clinical implications in carriers of CYP2C8*4, particularly in terms of their capacity to clear potent drugs and their susceptibility to adverse drug reactions.

Matched MeSH terms: Isoleucine/genetics*; Isoleucine/physiology*
The Effects of One Amino Acid Substitutions at the C-Terminal Region of Thermostable L2 Lipase by Computational and Experimental Approach

Sani HA, Shariff FM, Rahman RNZRA, Leow TC, Salleh AB

Mol Biotechnol, 2018 Jan;60(1):1-11.
PMID: 29058211 DOI: 10.1007/s12033-017-0038-3

The substitutions of the amino acid at the predetermined critical point at the C-terminal of L2 lipase may increase its thermostability and enzymatic activity, or even otherwise speed up the unfolding of the protein structure. The C-terminal of most proteins is often flexible and disordered. However, some protein functions are directly related to flexibility and play significant role in enzyme reaction. The critical point for mutation of L2 lipase structure was predicted at the position 385 of the L2 sequence, and the best three mutants were determined based on I-Mutant2.0 software. The best three mutants were S385E, S385I and S385V. The effects of the substitution of the amino acids at the critical point were analysed with molecular dynamics simulation by using Yet Another Scientific Artificial Reality Application software. The predicted mutant L2 lipases were found to have lower root mean square deviation value as compared to L2 lipase. It was indicated that all the three mutants had higher compactness in the structure, consequently enhanced the stability. Root mean square fluctuation analysis showed that the flexibility of L2 lipase was reduced by mutations. Purified S385E lipase had an optimum temperature of 80 °C in Tris-HCl pH 8. The highest enzymatic activity of purified S385E lipase was obtained at 80 °C temperature in Tris-HCl pH 8, while for L2 lipase it was at 70 °C in Glycine-NaOH pH 9. The thermal stability of S385V lipase was enhanced as compared to other protein since that the melting point (T m) value was at 85.96 °C. S385I lipase was more thermostable compared to recombinant L2 lipase and other mutants at temperature 60 °C within 16 h preincubation.

Matched MeSH terms: Isoleucine/genetics
Beta-ketothiolase deficiency in a Malaysian infant

Rajan D, Constance LSL, Brandon P

Med J Malaysia, 2019 04;74(2):174-175.
PMID: 31079130

Methylacetoacetyl-coenzyme A thiolase (MAT) deficiency is an autosomal recessive disease caused by a defect of mitochondrial acetoacetyl-CoA thiolase (T2). There is an error of isoleucine catabolism and ketone body utilization due to mutations in the acetyl-Coenzyme A acetyltransferase 1 (ACAT1) gene. We report a case of a 14 months old Sabahan boy with beta deficiency who presented with severe sepsis and ketoacidosis who subsequently recovered.

Matched MeSH terms: Isoleucine/metabolism
Fulltext The Effect of Isoleucine Supplementation on Body Weight Gain and Blood Glucose Response in Lean and Obese Mice

O'Rielly R, Li H, Lim SM, Yazbeck R, Kritas S, Ullrich SS, et al.

Nutrients, 2020 Aug 14;12(8).
PMID: 32823899 DOI: 10.3390/nu12082446

Chronic isoleucine supplementation prevents diet-induced weight gain in rodents. Acute-isoleucine administration improves glucose tolerance in rodents and reduces postprandial glucose levels in humans. However, the effect of chronic-isoleucine supplementation on body weight and glucose tolerance in obesity is unknown. This study aimed to investigate the impact of chronic isoleucine on body weight gain and glucose tolerance in lean and high-fat-diet (HFD) induced-obese mice. Male C57BL/6-mice, fed a standard-laboratory-diet (SLD) or HFD for 12 weeks, were randomly allocated to: (1) Control: Drinking water; (2) Acute: Drinking water with a gavage of isoleucine (300 mg/kg) prior to the oral-glucose-tolerance-test (OGTT) or gastric-emptying-breath-test (GEBT); (3) Chronic: Drinking water with 1.5% isoleucine, for a further six weeks. At 16 weeks, an OGTT and GEBT was performed and at 17 weeks metabolic monitoring. In SLD- and HFD-mice, there was no difference in body weight, fat mass, and plasma lipid profiles between isoleucine treatment groups. Acute-isoleucine did not improve glucose tolerance in SLD- or HFD-mice. Chronic-isoleucine impaired glucose tolerance in SLD-mice. There was no difference in gastric emptying between any groups. Chronic-isoleucine did not alter energy intake, energy expenditure, or respiratory quotient in SLD- or HFD-mice. In conclusion, chronic isoleucine supplementation may not be an effective treatment for obesity or glucose intolerance.

Matched MeSH terms: Isoleucine
Fulltext Urinary amino acids profile of vegetarians and non-vegetarians

Chia, Yoke Yin, Ton, So Ha

Malays J Nutr, 2006;12(1):67-78.
MyJurnal

The objective of the study was to quantify and to profile the amino acids content in urine samples. The amino acids content in urine was determined in 162 individuals (62 young non-vegetarians aged 15-45 years, 24 elderly non-vegetarians aged 46-70 years, 40 young vegetarians and 36 elderly vegetarians) by high performance liquid chromatography (HPLC). The most common amino acids detected in the young and elderly individuals on vegetarian and non-vegetarian diets were phenylalanine, threonine, arginine and asparagine, while leucine, aspartic acid and alanine were not found in any urine samples in both groups. Isoleucine was not detected in the urine of vegetarians. The concentrations of the majority of essential amino acids were between 0.10 - 2.00 mgl24hrs except for histidine which had a range of 4.1 - 5.0 mgl24hrs. The concentrations of non-essential amino acids varied. Proline, glycine and tyrosine concentrations were between 0.10 - 1.00 mg/24hrs, while cysteine, glutamine, glutamic acid and cystine concentrations were between 11.0 - 21.0 mg124hrs. Asparagine and hydroxy-proline had a range of 0.10 - 5.00 mg/24hrs, while serine and arginine ranged between 31.0 - 50.0 mg124hrs. Isoleucine and serine were not detected in elderly vegetarians while histidine, glycine, glutamic acid and hydroxy-proline were not detected in elderly non-vegetarians. Isoleucine, glycine and hydroxy proline were detected in young non-vegetarians but not in young vegetarians. The levels of amino acids showed no significant statistical differences between young vegetarians and non-vegetarians as well as between elderly vegetarians and non-vegetarians. Phenylalanine, threonine and trypthophan were commonly detected in the lacto-ovo and lacto vegetarians, while valine, cysteine, arginine and asparagine were commonly detected in vegans. In conclusion, except for isoleucine, general differences were seen in urinary amino acid excretions between vegetarians and non-vegetarians even though the differences were statistically not significant. Therefore lacto-ovo diets could be nutritionally adequate as the nutrients were substituted by dairy or plant products.

Matched MeSH terms: Isoleucine
Fulltext A response surface approach on hydrolysis condition of eel (Monopterus Sp.) protein hydrolysate with antioxidant activity

Halim, N. R. A., Sarbon, N. M.

International Food Research Journal, 2017;24(3):1081-1093.
MyJurnal

The study aims to determine the optimized condition of eel protein hydrolysate (EPH)
produced using alcalase. The proximate compositions of eel flesh were determined as well.
Enzymatic hydrolysis conditions were optimized using response surface methodology (RSM)
by applying four factors, 3-levels Central Composite Design (CCD) with six centre points. The
model equation was proposed with regards to the time (60min, 120min, 180min), temperature
(40°C, 50°C, 60°C), pH (7, 8, 9) and enzyme concentration (1%, 2%, 3%). The optimum of
hydrolysis condition that be suggested to obtain the optimum yield, degree of hydrolysis (DH)
and antioxidant activity were 84.02 min, 50.18°C, pH 7.89 and 2.26% [enzyme]. The predicted
response values using quadratic model were 10.03% for yield, 83.23% for DH and 89.24%
for antioxidant activity. The chemical composition determination showed that the protein
content increased by more than 5-fold (16.88% to 98.53%) while the fat content was decreased
by 96.48% after hydrolysis. Hydrolysis process had significantly increased the amount of
both hydrophilic (serine and threonine) and hydrophobic amino acids (valine, isoleucine,
phenylalanine, methionine) which contributed to the antioxidant activity of hydrolyzed eel
protein. The enzymatic hydrolysis of eel protein had improved the protein content of EPH with
potential as new natural antioxidant.

Matched MeSH terms: Isoleucine
Fulltext Biochemical and texture property changes during molting process of tiger prawn, Penaeus monodon

Nor Faadila, M.I., Harivaindaran, K.V., Tajul, A. Yang

International Food Research Journal, 2013;20(2):751-758.
MyJurnal

Texture and biochemical changes, specifically in moisture, protein content and amino acid profile were studied throughout the molt cycle of Panaeus monodon. This study was initiated to investigate changes that may occur in mass and tissue composition during different molting stages. Molting of Penaeus monodon are classified into 3 main stages; postmolt, intermolt and premolt. Result of biochemical analysis, shows that moisture varies from 78.02-80.88%, indicating a maximum value during postmolt and minimum value during premolt. Total protein content was found to be higher during intermolt (23.48%) and postmolt (22.27%) compared to premolt (23.10%). The result of SDS-PAGE electrophoresis shows a higher intensity of protein band during intermolt which corresponds to higher protein content. Thus, this electrophoresis method is useful as an alternative to determine different stages of shrimp molting. This is based on intensity of the protein band which is referring to protein content of the shrimp at its different stages. The amino acid profile showed that arginine, alanine, glutamic acid, glycine, lycine, and thronine increased during premolt whilst isoleucine and phenylalanine higher during postmolt. Aspartic acid and histidine was higher in intermolt than in premolt and postmolt. Texture analysis carried out give an elastic modulus value that is high during premolt compared to postmolt and intermolt. There are significant changes in texture and biochemical composition through elastic modules value and protein composition of Penaeus monodon during each stages of moltcycle.

Matched MeSH terms: Isoleucine
Nutritional requirements for in vitro cultivation of a simian malarial parasite, Plasmodium knowlesi

Siddiqui WA, Schnell JV, Geiman QM

Mil Med, 1969 Sep;134(10):929-38.
PMID: 4987068
Matched MeSH terms: Isoleucine
ABCA1 gene polymorphisms and their associations with coronary artery disease and plasma lipids in males from three ethnic populations in Singapore

Tan JH, Low PS, Tan YS, Tong MC, Saha N, Yang H, et al.

Hum Genet, 2003 Jul;113(2):106-17.
PMID: 12709788

Mutations in the ATP-binding cassette transporter ABCA1 underlie Tangier disease and familial hypoalphaliproteinemia (FHA), disorders that are characterised by reduced high-density lipoprotein-cholesterol (HDL-C) concentration and cholesterol efflux, and increased coronary artery disease (CAD). We explored if polymorphisms in the ABCA1 gene are associated with CAD and variations in plasma lipid levels, especially HDL-C, and whether the associations may depend on ethnicity. Male cases and controls from the Singapore Chinese, Malay and Indian populations were genotyped for five ABCA1 single nucleotide polymorphisms. Various single-locus frequency distribution differences between cases and controls were detected in different ethnic groups: the promoter -14C>T in Indians, exon 18 M883I in Malays, and 3'-untranslated (UTR) region 8994A>G in Chinese. For the Malay population, certain haplotypes carrying the I825- A (exon 17) and M883- G alleles were more frequent among cases than controls, whereas the converse was true for the alternative configuration of V825- G and I883- A, and this association was reinforced in multi-locus disequilibrium analysis that utilized genotypic data. In the healthy controls, associations were found for -14C>T genotypes with HDL-C in Chinese; 237indelG (5'UTR) with apolipoprotein A1 (apoA1) in Malays and total cholesterol (TC) in Indians; M883I with lipoprotein(a) [Lp(a)] in Malays and apolipoprotein B (apoB) in Chinese; and 8994A>G with Lp(a) in Malays, and TC, low-density lipoprotein-cholesterol (LDL-C) as well as apoB in Indians. While genotype-phenotype associations were not reproduced across populations and loci, V825I and M883I were clearly associated with CAD status in Malays with no effects on HDL-C or apoA1.

Matched MeSH terms: Isoleucine/genetics
Fulltext Chemical composition and molecular structure of polysaccharide-protein biopolymer from Durio zibethinus seed: extraction and purification process

Amid BT, Mirhosseini H, Kostadinović S

Chem Cent J, 2012 Oct 14;6(1):117.
PMID: 23062269 DOI: 10.1186/1752-153X-6-117

BACKGROUND: The biological functions of natural biopolymers from plant sources depend on their chemical composition and molecular structure. In addition, the extraction and further processing conditions significantly influence the chemical and molecular structure of the plant biopolymer. The main objective of the present study was to characterize the chemical and molecular structure of a natural biopolymer from Durio zibethinus seed. A size-exclusion chromatography coupled to multi angle laser light-scattering (SEC-MALS) was applied to analyze the molecular weight (Mw), number average molecular weight (Mn), and polydispersity index (Mw/Mn).
RESULTS: The most abundant monosaccharide in the carbohydrate composition of durian seed gum were galactose (48.6-59.9%), glucose (37.1-45.1%), arabinose (0.58-3.41%), and xylose (0.3-3.21%). The predominant fatty acid of the lipid fraction from the durian seed gum were palmitic acid (C16:0), palmitoleic acid (C16:1), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:2). The most abundant amino acids of durian seed gum were: leucine (30.9-37.3%), lysine (6.04-8.36%), aspartic acid (6.10-7.19%), glycine (6.07-7.42%), alanine (5.24-6.14%), glutamic acid (5.57-7.09%), valine (4.5-5.50%), proline (3.87-4.81%), serine (4.39-5.18%), threonine (3.44-6.50%), isoleucine (3.30-4.07%), and phenylalanine (3.11-9.04%).
CONCLUSION: The presence of essential amino acids in the chemical structure of durian seed gum reinforces its nutritional value.

Matched MeSH terms: Isoleucine
LC-MS analysis reveals biological and metabolic processes essential for Candida albicans biofilm growth

Munusamy K, Loke MF, Vadivelu J, Tay ST

Microb Pathog, 2021 Mar;152:104614.
PMID: 33202254 DOI: 10.1016/j.micpath.2020.104614

Candidiasis is the most common fungal infection associated with high morbidity and mortality among immunocompromised patients. The ability to form biofilm is essential for Candida albicans pathogenesis and drug resistance. In this study, the planktonic cell and biofilm proteomes of C. albicans SC5314 strain analyzed using Liquid Chromatography-Mass Spectrometry (LC-MS) were compared. In total, 280 and 449 proteins are annotated from the planktonic cell and biofilm proteomes, respectively. The biofilm proteome demonstrated significantly higher proportion of proteins associated with the endomembrane system, mitochondrion and cytoplasm than planktonic proteome. Among proteins detected, 143 and 207 biological processes are annotated, of which, 38 and 102 are specific to the planktonic cell and biofilm proteomes, respectively, while 105 are common biological processes. The specific biological processes of C. albicans planktonic cell proteome are associated with cell polarity, energy metabolism and nucleotide (purine) metabolism, oxido-reduction coenzyme metabolic process, monosaccharide and amino acid (methionine) biosynthesis, regulation of anatomical structure morphogenesis and cell cycling, and single organism reproduction. Meanwhile, regulation of cellular macromolecule biosynthesis and metabolism, transcription and gene expression are major biological processes specifically associated with C. albicans biofilm proteome. Biosynthesis of leucine, isoleucine, and thiocysteine are highlighted as planktonic-related pathways, whereas folate metabolism, fatty acid metabolism and biosynthesis of amino acids (lysine, serine and glycine) are highlighted as biofilm-related pathways. In summary, LC-MS-based proteomic analysis reveals different adaptative strategies of C. albicans via specific biological and metabolic processes for planktonic cell and biofilm lifestyles. The mass spectrometry data are available via ProteomeXchange with identifiers PXD007830 (for biofilm proteome) and PXD007831 (for planktonic cell proteome).

Matched MeSH terms: Isoleucine
Fulltext Metabolomics analysis of herb-partitioned moxibustion treatment on rats with diarrhea-predominant irritable bowel syndrome

Lin X, Liu X, Xu J, Cheng KK, Cao J, Liu T, et al.

Chin Med, 2019;14:18.
PMID: 31080495 DOI: 10.1186/s13020-019-0240-2

Background: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, which is commonly treated with antidiarrhoeal, antispasmodics, serotonergic agents or laxative agents. These treatments provide relief for IBS symptoms but may also lead to undesired side effects. Previously, herb-partitioned moxibustion (HPM) treatment has been demonstrated to be effective in ameliorating symptoms of IBS. However, the underlying mechanism of this beneficial treatment is yet to be established. The aim of the current study was to systematically assess the metabolic alterations in response to diarrhea-predominant IBS (IBS-D) and therapeutic effect of HPM.
Methods: Proton nuclear magnetic resonance spectroscopy (1H NMR)-based metabolomics approach was used to investigate fecal and serum metabolome of rat model of IBS-D with and without HPM treatment.
Results: The current results showed that IBS-induced metabolic alterations in fecal and serum sample include higher level of threonine and UDP-glucose together with lower levels of aspartate, ornithine, leucine, isoleucine, proline, 2-hydroxy butyrate, valine, lactate, ethanol, arginine, 2-oxoisovalerate and bile acids. These altered metabolites potentially involve in impaired gut secretory immune system and intestinal inflammation, malabsorption of nutrients, and disordered metabolism of bile acids. Notably, the HPM treatment was found able to normalize the Bristol stool forms scale scores, fecal water content, plasma endotoxin level, and a number of IBS-induced metabolic changes.
Conclusions: These findings may provide useful insight into the molecular basis of IBS and mechanism of the HPM intervention.

Matched MeSH terms: Isoleucine

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