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Formation and reduction of 5-hydroxymethylfurfural at frying temperature in model system as a function of amino acid and sugar composition

Kavousi P, Mirhosseini H, Ghazali H, Ariffin AA

Food Chem, 2015 Sep 1;182:164-70.
PMID: 25842323 DOI: 10.1016/j.foodchem.2015.02.135

5-Hydroxymethylfurfural (HMF) is formed during heat treatment of carbohydrate-containing foods, especially in a deep-fat frying process. This study aimed to investigate the effect of amino acids on the formation and reduction of HMF from glucose, fructose and sucrose at frying temperature in model systems containing binary mixtures of an amino acid and a sugar in equal concentrations (0.3M). The results revealed that the formation of HMF from sugars accelerated in the presence of acidic amino acids (i.e. glutamic and aspartic acids). Conversely, the presence of basic amino acids (i.e. lysine, arginine and histidine) led to reduced concentrations of HMF to non-detectable levels in model systems. The results showed that both pH and heating time significantly affected the formation of HMF from fructose in the presence of glutamic acid. In this regard, a higher amount of HMF was formed at lower pH.

Matched MeSH terms: Amino Acids/analysis*; Amino Acids/chemistry
Substrate specificity of king cobra (Ophiophagus hannah) venom L-amino acid oxidase

Tan NH, Saifuddin MN

Int. J. Biochem., 1991;23(3):323-7.
PMID: 2044840

1. Substrate specificity of purified king cobra (Ophiophagus hannah) venom L-amino acid oxidase was investigated. 2. The enzyme was highly specific for the L-enantiomer of amino acid. Effective oxidation of L-amino acid by the enzyme requires the presence of a free primary alpha-amino group but the alpha-carboxylate group is not as critical for the catalysis. 3. The enzyme was very active against L-Lys, L-Phe, L-Leu, L-Tyr, L-Tryp, L-Arg, L-Met, L-ornithine, L-norleucine and L-norvaline and moderately active against L-His, L-cystine and L-Ileu. Other L-amino acids were oxidized slowly or not oxidized. 4. The data suggest the presence of a side chain binding site in the enzyme, and that the binding site comprises at least five 'subsites': the hydrophobic subsites a, b and c; and the two 'amino' binding subsites d and e. Subsite b appears to be able to accommodate two methylene/methyl carbons.

Matched MeSH terms: Amino Acids/metabolism; Amino Acids/chemistry
Fulltext Modulation of Crustacean Innate Immune Response by Amino Acids and Their Metabolites: Inferences From Other Species

Huang Z, Aweya JJ, Zhu C, Tran NT, Hong Y, Li S, et al.

Front Immunol, 2020;11:574721.
PMID: 33224140 DOI: 10.3389/fimmu.2020.574721

Aquaculture production of crustaceans (mainly shrimp and crabs) has expanded globally, but disease outbreaks and pathogenic infections have hampered production in the last two decades. As invertebrates, crustaceans lack an adaptive immune system and mainly defend and protect themselves using their innate immune system. The immune system derives energy and metabolites from nutrients, with amino acids constituting one such source. A growing number of studies have shown that amino acids and their metabolites are involved in the activation, synthesis, proliferation, and differentiation of immune cells, as well as in the activation of immune related signaling pathways, reduction of inflammatory response and regulation of oxidative stress. Key enzymes in amino acid metabolism have also been implicated in the regulation of the immune system. Here, we reviewed the role played by amino acids and their metabolites in immune-modulation in crustaceans. Information is inferred from mammals and fish where none exists for crustaceans. Research themes are identified and the relevant research gaps highlighted for further studies.

Matched MeSH terms: Amino Acids/immunology*; Amino Acids/metabolism
Characterization of Polar and Non-Polar Compounds of House Edible Bird's Nest (EBN) from Johor, Malaysia

Hun Lee T, Hau Lee C, Alia Azmi N, Kavita S, Wong S, Znati M, et al.

Chem Biodivers, 2020 Jan;17(1):e1900419.
PMID: 31721431 DOI: 10.1002/cbdv.201900419

This work investigated the polar (PC: protein, amino acid and metabolite) and non-polar (NPC: fatty acid) compounds and bioactivity characteristics of the EBN harvested from the state of Johor in Malaysia. The electrophoretic gels exhibited 15 protein bands (16-173 kD) with unique protein profile. Amino acids analysis by AccQ⋅Tag method revealed 18 types of amino acids in EBN. Metabolite profiling was performed using High-Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometer (HPLC-QTOF/MS) technique and a total of 54 compounds belonging to different groups were detected and identified. These findings help to uncover the relation of therapeutic activity of EBN. The EBN was further extracted with AcOEt and BuOH. The AcOEt extract was fractionated into three fractions (F1 -F3 ), and the high triglyceride content in F2 was verified by gC-FID. The three groups of fatty acids discovered in EBN are 48.43 % of poly-unsaturated (PUFA), 25.35 % of saturated fatty acids (SFA) and 24.74 % of mono-unsaturated fat (MUFA). This is the first time to report results ofEBN, BuOH, and AcOEt extracts and of fraction F2 (TEBN) on their analysis for their antioxidant activities by DPPH, ABTS and catalase assay and for their paraoxonase and anti-tyrosinase activities. The results showed that TEBN exhibited the significant bioactivity in all assays. These findings suggest that TEBN is a good source for natural bioactive compounds in promoting body vigor. Current work widened the content of EBN especially on the triglyceride and also marked the content of specific location (Johor, Malaysia) of EBN origin.

Matched MeSH terms: Amino Acids/analysis*; Amino Acids/chemistry
Deciphering the catalytic amino acid residues of l-2-haloacid dehalogenase (DehL) from Rhizobium sp. RC1: An in silico analysis

Adamu A, Wahab RA, Shamsir MS, Aliyu F, Huyop F

Comput Biol Chem, 2017 Oct;70:125-132.
PMID: 28873365 DOI: 10.1016/j.compbiolchem.2017.08.007

The l-2-haloacid dehalogenases (EC 3.8.1.2) specifically cleave carbon-halogen bonds in the L-isomers of halogenated organic acids. These enzymes have potential applications for the bioremediation and synthesis of various industrial products. One such enzyme is DehL, the l-2-haloacid dehalogenase from Rhizobium sp. RC1, which converts the L-isomers of 2-halocarboxylic acids into the corresponding D-hydroxycarboxylic acids. However, its catalytic mechanism has not been delineated, and to enhance its efficiency and utility for environmental and industrial applications, knowledge of its catalytic mechanism, which includes identification of its catalytic residues, is required. Using ab initio fragment molecular orbital calculations, molecular mechanics Poisson-Boltzmann surface area calculations, and classical molecular dynamic simulation of a three-dimensional model of DehL-l-2-chloropropionic acid complex, we predicted the catalytic residues of DehL and propose its catalytic mechanism. We found that when Asp13, Thr17, Met48, Arg51, and His184 were individually replaced with an alanine in silico, a significant decrease in the free energy of binding for the DehL-l-2-chloropropionic acid model complex was seen, indicating the involvement of these residues in catalysis and/or structural integrity of the active site. Furthermore, strong inter-fragment interaction energies calculated for Asp13 and L-2-chloropropionic acid, and for a water molecule and His184, and maintenance of the distances between atoms in the aforementioned pairs during the molecular dynamics run suggest that Asp13 acts as the nucleophile and His184 activates the water involved in DehL catalysis. The results of this study should be important for the rational design of a DehL mutant with improved catalytic efficiency.

Matched MeSH terms: Amino Acids/metabolism*; Amino Acids/chemistry
Fulltext Improved prediction and characterization of anticancer activities of peptides using a novel flexible scoring card method

Charoenkwan P, Chiangjong W, Lee VS, Nantasenamat C, Hasan MM, Shoombuatong W

Sci Rep, 2021 Feb 04;11(1):3017.
PMID: 33542286 DOI: 10.1038/s41598-021-82513-9

As anticancer peptides (ACPs) have attracted great interest for cancer treatment, several approaches based on machine learning have been proposed for ACP identification. Although existing methods have afforded high prediction accuracies, however such models are using a large number of descriptors together with complex ensemble approaches that consequently leads to low interpretability and thus poses a challenge for biologists and biochemists. Therefore, it is desirable to develop a simple, interpretable and efficient predictor for accurate ACP identification as well as providing the means for the rational design of new anticancer peptides with promising potential for clinical application. Herein, we propose a novel flexible scoring card method (FSCM) making use of propensity scores of local and global sequential information for the development of a sequence-based ACP predictor (named iACP-FSCM) for improving the prediction accuracy and model interpretability. To the best of our knowledge, iACP-FSCM represents the first sequence-based ACP predictor for rationalizing an in-depth understanding into the molecular basis for the enhancement of anticancer activities of peptides via the use of FSCM-derived propensity scores. The independent testing results showed that the iACP-FSCM provided accuracies of 0.825 and 0.910 as evaluated on the main and alternative datasets, respectively. Results from comparative benchmarking demonstrated that iACP-FSCM could outperform seven other existing ACP predictors with marked improvements of 7% and 17% for accuracy and MCC, respectively, on the main dataset. Furthermore, the iACP-FSCM (0.910) achieved very comparable results to that of the state-of-the-art ensemble model AntiCP2.0 (0.920) as evaluated on the alternative dataset. Comparative results demonstrated that iACP-FSCM was the most suitable choice for ACP identification and characterization considering its simplicity, interpretability and generalizability. It is highly anticipated that the iACP-FSCM may be a robust tool for the rapid screening and identification of promising ACPs for clinical use.

Matched MeSH terms: Amino Acids/genetics; Amino Acids/chemistry
Structural and Functional Characterization of Conserved Key Amino Acids in Lipoteichoic Acid Synthase LtaS of Lactiplantibacillus plantarum

Cai Z, Yuan X, Zhong G, Zhang T, He J, Dang Y, et al.

J Agric Food Chem, 2025 Jan 29;73(4):2623-2633.
PMID: 39834201 DOI: 10.1021/acs.jafc.4c08913

Lipoteichoic acid synthase (LtaS) is crucial for the biosynthesis of lipoteichoic acid (LTA) in lactic acid bacteria (LAB), where LTA plays a key role in bacterial adhesion, immune modulation, and maintaining cell integrity. This study explores the regulation of LtaS activity in Lactiplantibacillus plantarum, examining the effects of factors such as temperature, pH, and metal ions on enzyme activity. Molecular docking was used to identify critical amino acids at the enzyme's active site, and site-directed mutagenesis confirmed the role of five key residues (Glu-259, Thr-303, Asn-353, Arg-360, and His-420) in LtaS activity. Among them, Thr-303 plays a pivotal role, followed by Glu-259 and His-420. Conservation analysis revealed that these active-site residues are highly conserved across LAB species. These findings provide valuable insights into the functional properties of LtaS, offering potential for enhancing the efficacy of LAB-based probiotics and improving their therapeutic benefits in health applications.

Matched MeSH terms: Amino Acids/metabolism; Amino Acids/chemistry
Fulltext Angiotensin-I Converting Enzyme (ACE) Inhibitory and Anti-Oxidant Activities of Sea Cucumber (Actinopyga lecanora) Hydrolysates

Ghanbari R, Zarei M, Ebrahimpour A, Abdul-Hamid A, Ismail A, Saari N

Int J Mol Sci, 2015 Dec 04;16(12):28870-85.
PMID: 26690117 DOI: 10.3390/ijms161226140

In recent years, food protein-derived hydrolysates have received considerable attention because of their numerous health benefits. Amongst the hydrolysates, those with anti-hypertensive and anti-oxidative activities are receiving special attention as both activities can play significant roles in preventing cardiovascular diseases. The present study investigated the angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities of Actinopyga lecanora (A. lecanora) hydrolysates, which had been prepared by alcalase, papain, bromelain, flavourzyme, pepsin, and trypsin under their optimum conditions. The alcalase hydrolysate showed the highest ACE inhibitory activity (69.8%) after 8 h of hydrolysis while the highest anti-oxidative activities measured by 2,2-diphenyl 1-1-picrylhydrazyl radical scavenging (DPPH) (56.00%) and ferrous ion-chelating (FIC) (59.00%) methods were exhibited after 24 h and 8 h of hydrolysis, respectively. The ACE-inhibitory and anti-oxidative activities displayed dose-dependent trends, and increased with increasing protein hydrolysate concentrations. Moreover, strong positive correlations between angiotensin-I converting enzyme (ACE) inhibitory and anti-oxidative activities were also observed. This study indicates that A. lecanora hydrolysate can be exploited as a source of functional food owing to its anti-oxidant as well as anti-hypertension functions.

Matched MeSH terms: Amino Acids/pharmacology; Amino Acids/chemistry
Hypoglycemic effects of cocoa (Theobroma cacao L.) autolysates

Sarmadi B, Aminuddin F, Hamid M, Saari N, Abdul-Hamid A, Ismail A

Food Chem, 2012 Sep 15;134(2):905-11.
PMID: 23107706 DOI: 10.1016/j.foodchem.2012.02.202

Fat, alkaloid and polyphenol contents of two clones of cocoa (UIT1 and PBC 140) were removed and the remaining powder was autolyzed at pH 3.5 and 5.2. Based on the results, autolysates of UIT produced at pH 3.5 exhibited the highest ability to inhibit α-amylase activity. However, no α-glucosidase inhibition activity was observed under the conditions specified. Autolysates produced under pH 3.5 caused the highest amount of insulin secretion. In streptozotocin-diabetic rats, all cocoa autolysates significantly decreased blood glucose at 4h. To assure that the results from the assays were not due to the polyphenols of cocoa autolysates qualitative and quantitative tests were applied. According to their results cocoa autolysates were found to be free from polyphenols. Analysis of amino acid composition revealed that cocoa autolysates were abundant in hydrophobic amino acids. It can be suggested that besides other compounds of cocoa, its peptides and amino acids could contribute to its health benefits.

Matched MeSH terms: Amino Acids/analysis; Amino Acids/metabolism
Microbial dynamics, metabolomic profiles, and the correlation between them during fermentation of serofluid dish

Wei J, Ren W, Wang L, Liu M, Tian X, Ding G, et al.

J Sci Food Agric, 2020 Dec;100(15):5627-5636.
PMID: 32712996 DOI: 10.1002/jsfa.10690

BACKGROUND: Serofluid dish, a traditional Chinese fermented food, possesses unique flavors and health beneficial effects. These properties are likely due to the sophisticated metabolic networks during fermentation, which are mainly driven by microbiota. However, the exact roles of metabolic pathways and the microbial community during this process remain equivocal.
RESULTS: Here, we investigated the microbial dynamics by next-generation sequencing, and outlined a differential non-targeted metabolite profiling in the process of serofluid dish fermentation using the method of hydrophilic interaction liquid chromatography column with ultra-high-performance liquid chromatography-quadruple time-of-flight mass spectrometry. Lactobacillus was the leading genus of bacteria, while Pichia and Issatchenkia were the dominant fungi. They all accumulated during fermentation. In total, 218 differential metabolites were identified, of which organic acids, amino acids, sugar and sugar alcohols, fatty acids, and esters comprised the majority. The constructed metabolic network showed that tricarboxylic acid cycle, urea cycle, sugar metabolism, amino acids metabolism, choline metabolism, and flavonoid metabolism were regulated by the fermentation. Furthermore, correlation analysis revealed that the leading fungi, Pichia and Issatchenkia, were linked to organic acids, amino acid and sugar metabolism, flavonoids, and several other flavor and functional components. Antibacterial tests indicated the antibacterial effect of serofluid soup against Salmonella and Staphylococcus.
CONCLUSION: This work provides new insights into the complex microbial and metabolic networks during serofluid dish fermentation, and a theoretical basis for the optimization of its industrial production. © 2020 Society of Chemical Industry.

Matched MeSH terms: Amino Acids/analysis; Amino Acids/metabolism
Cancer Cell Metabolites: Updates on Current Tracing Methods

Maniam S, Maniam S

Chembiochem, 2020 12 11;21(24):3476-3488.
PMID: 32639076 DOI: 10.1002/cbic.202000290

Cancer is the second leading cause of death-1 in 6 deaths globally is due to cancer. Cancer metabolism is a complex and one of the most actively researched area in cancer biology. Metabolic reprogramming in cancer cells entails activities that involve several enzymes and metabolites to convert nutrient into building blocks that alter energy metabolism to fuel rapid cell division. Metabolic dependencies in cancer generate signature metabolites that have key regulatory roles in tumorigenesis. In this minireview, we highlight recent advances in the popular methods ingrained in biochemistry research such as stable and flux isotope analysis, as well as radioisotope labeling, which are valuable in elucidating cancer metabolites. These methods together with analytical tools such as chromatography, nuclear magnetic resonance spectroscopy and mass spectrometry have helped to bring about exploratory work in understanding the role of important as well as obscure metabolites in cancer cells. Information obtained from these analyses significantly contribute in the diagnosis and prognosis of tumors leading to potential therapeutic targets for cancer therapy.

Matched MeSH terms: Amino Acids/metabolism; Amino Acids/chemistry
Fulltext Protein-Protein Interactions: Insight from Molecular Dynamics Simulations and Nanoparticle Tracking Analysis

Chong WL, Chupradit K, Chin SP, Khoo MM, Khor SM, Tayapiwatana C, et al.

Molecules, 2021 Sep 20;26(18).
PMID: 34577167 DOI: 10.3390/molecules26185696

Protein-protein interaction plays an essential role in almost all cellular processes and biological functions. Coupling molecular dynamics (MD) simulations and nanoparticle tracking analysis (NTA) assay offered a simple, rapid, and direct approach in monitoring the protein-protein binding process and predicting the binding affinity. Our case study of designed ankyrin repeats proteins (DARPins)-AnkGAG1D4 and the single point mutated AnkGAG1D4-Y56A for HIV-1 capsid protein (CA) were investigated. As reported, AnkGAG1D4 bound with CA for inhibitory activity; however, it lost its inhibitory strength when tyrosine at residue 56 AnkGAG1D4, the most key residue was replaced by alanine (AnkGAG1D4-Y56A). Through NTA, the binding of DARPins and CA was measured by monitoring the increment of the hydrodynamic radius of the AnkGAG1D4-gold conjugated nanoparticles (AnkGAG1D4-GNP) and AnkGAG1D4-Y56A-GNP upon interaction with CA in buffer solution. The size of the AnkGAG1D4-GNP increased when it interacted with CA but not AnkGAG1D4-Y56A-GNP. In addition, a much higher binding free energy (∆GB) of AnkGAG1D4-Y56A (-31 kcal/mol) obtained from MD further suggested affinity for CA completely reduced compared to AnkGAG1D4 (-60 kcal/mol). The possible mechanism of the protein-protein binding was explored in detail by decomposing the binding free energy for crucial residues identification and hydrogen bond analysis.

Matched MeSH terms: Amino Acids/metabolism; Amino Acids/chemistry
Inborn errors of metabolic diseases in Malaysia: a preliminary report of maple syrup urine diseases for 1993

Zakiah I, Ashikin YN, Aisiah SM, Ismail HI

Southeast Asian J Trop Med Public Health, 1995;26 Suppl 1:134-6.
PMID: 8629092

The Malaysian level of health care has greatly improved so that many of the infectious diseases are now under control. However, perinatal death or death due to unknown childhood diseases remains high (10.3%) being second on the list of causes of death amongst Malaysians. Could inborn metabolic diseases be the main cause of death among these children? Recently, with our success in the development of confirmatory techniques for amino acid disorders using high performance liquid chromatography (HPLC), we have examined 404 samples received from all over the country in 1993. Each specimen with abnormal findings from screening tests by one-dimensional thin layer chromatography was confirmed using HPLC. 41% had generalized aminoacidurias and 4.2% had maple syrup urine disease (MSUD). Patients were aged between 11 days to 6 years. Most of them were Malay males and presented with a history suggestive of MSUD. With this preliminary finding, further studies will be carried out in order to have an investigation and management protocol for the diseases and more importantly to formulate a strategy of screening for the country.

Matched MeSH terms: Amino Acids/blood*; Amino Acids/urine
LC-MS/MS-based metabolomics and multivariate statistical analysis reveal the mechanism of yeast extracellular proteases on myofibrillar protein degradation, metabolite development and sensory characteristics improvement

Li D, Liang Y, Xia Q, Pan D, Du L, He J, et al.

Food Microbiol, 2025 Jun;128:104715.
PMID: 39952759 DOI: 10.1016/j.fm.2024.104715

Yeast extracellular proteases play a key role in developing the taste of dry-cured ham, whereas the mechanism of yeast proteases on taste formation of dry-cured ham is not fully studied. The proteases characteristics of yeast isolated form Jinhua ham, hydrolysis capacities for myofibrillar proteins (MP), free amino acid contents, metabolite compositions, taste parameters and the relationship between metabolites and taste parameters were investigated to reveal the mechanism of Rhodotorula mucilaginosa AUMC 9298 (RM) and Candida parapsilosis d70a (CP) proteases on MP hydrolysis and taste development of dry-cured ham. The proteases of RM and CP showed high hydrolysis activities at the conditions of pH 5.0-8.0 and 30-50 °C. The proteases of RM showed higher capability to degrade myosin compared with CP proteases and Pichia kudriavzevii XS-5 (PK) proteases. The total free amino acid contents increased from 18.44 mg/100 mL in PK to 33.91 mg/100 mL in RM and 25.28 mg/100 mL in CP after 4 h hydrolysis of MP. Thirty-two metabolites were identified by LC-MS/MS, and peptides and amino acid derivatives were the key components of MP hydrolysates. The scores of umami, richness and aftertaste showed the largest values in RM among these groups. PLS-DA and correlation demonstrated that aspartic acid, N-Methyl-aspartic acid, Glu-Glu, γ-Glu-Cys, glutamic acid, γ-Glu-Glu and γ-Glu-Gln were positive correlation with the improvement of umami, richness and aftertaste.

Matched MeSH terms: Amino Acids/analysis; Amino Acids/metabolism
Fulltext Amino acid sequence and structural comparison of BACE1 and BACE2 using evolutionary trace method

Mirsafian H, Mat Ripen A, Merican AF, Bin Mohamad S

ScientificWorldJournal, 2014;2014:482463.
PMID: 25254246 DOI: 10.1155/2014/482463

Beta-amyloid precursor protein cleavage enzyme 1 (BACE1) and beta-amyloid precursor protein cleavage enzyme 2 (BACE2), members of aspartyl protease family, are close homologues and have high similarity in their protein crystal structures. However, their enzymatic properties differ leading to disparate clinical consequences. In order to identify the residues that are responsible for such differences, we used evolutionary trace (ET) method to compare the amino acid conservation patterns of BACE1 and BACE2 in several mammalian species. We found that, in BACE1 and BACE2 structures, most of the ligand binding sites are conserved which indicate their enzymatic property of aspartyl protease family members. The other conserved residues are more or less randomly localized in other parts of the structures. Four group-specific residues were identified at the ligand binding site of BACE1 and BACE2. We postulated that these residues would be essential for selectivity of BACE1 and BACE2 biological functions and could be sites of interest for the design of selective inhibitors targeting either BACE1 or BACE2.

Matched MeSH terms: Amino Acids/genetics; Amino Acids/metabolism; Amino Acids/chemistry
Fulltext Salutary value of haruan, the striped snakehead Channa striatus - a review

Haniffa MA, Sheela PA, Kavitha K, Jais AM

Asian Pac J Trop Biomed, 2014 May;4(Suppl 1):S8-S15.
PMID: 25183152 DOI: 10.12980/APJTB.4.2014C1015

Murrel namely Channa striatus or haruan contains all essential elements to maintain good health and to recover the lost energy after prolonged illness. The fatty acid composition (% of total fatty acid) indicated the abundant presence of C16:0 fatty acid as 30% and the other major fatty acids were C22:6 (15%), C20:4 (19%), C18:1 (12%) and C18:0 (15%). Haruan contains arachidonic acid (C20:4) as 19.0%, a precursor for prostaglandin and thromboxane biosyntheses. Both fatty and amino acids are important components for wound healing processes. Both the fillet and mucus extracts of haruan were found to exhibit a concentration dependent antinociceptive activity. In vitro antioxidant activity was higher in Channa roe protein hydrolysate than in Labeo roe protein hydrolysate in both DPPH radical scavenging and ferric reducing power. Protein content of roe concentrates (RPC) was found to be 90.2% (Channa) and 82.5% (Lates). Water absorption, oil absorption, foam capacity, stability and emulsifying capacity were found to be higher in Channa RPC than in Lates RPC. Characterization of protein hydrolysates from muscle and myofibrillar samples of haruan showed different kinetic and proteolytic activities. The skin extract of haruan influences the serotonergic receptor system thus they can function as an anti-depressant. Thus, haruan is the best example for food as medicine.

Matched MeSH terms: Amino Acids
Nutritional compositions and bioactivities of Dacryodes species: a review

Tee LH, Yang B, Nagendra KP, Ramanan RN, Sun J, Chan ES, et al.

Food Chem, 2014 Dec 15;165:247-55.
PMID: 25038673 DOI: 10.1016/j.foodchem.2014.05.084

Dacryodes species are evergreen, perennial trees with fleshy fruits and belong to the family Buseraseae. Many Dacryodes species are underutilized but are widely applied in traditional folk medicine to treat malaria, fever and skin diseases. The nutritional compositions, phytochemicals and biological activities of Dacryodes edulis, Dacryodes rostrata, Dacryodes buettneri, Dacryodes klaineana and Dacryodes hexandra are presented. The edible fruits of D. edulis are rich in lipids, proteins, vitamins, fatty acids and amino acids. Its extracts (leaf, fruit and resin) exhibit antioxidant, anti-microbial, anti-carcinogenic and other bioactivities. D. rostrata fruit has significant nutrient content, and is rich in proteins, lipids and minerals. These fruits are also highly rich in polyphenols, anthocyanins and antioxidant activities. This comprehensive review will assist the reader in understanding the nutritional benefits of Dacryodes species and in identifying current research needs.

Matched MeSH terms: Amino Acids
Fulltext Kinetic characterization of Channa striatus muscle sarcoplasmic and myofibrillar protein hydrolysates

Ghassem M, Fern SS, Said M, Ali ZM, Ibrahim S, Babji AS

J Food Sci Technol, 2014 Mar;51(3):467-75.
PMID: 24587521 DOI: 10.1007/s13197-011-0526-6

This study was conducted to evaluate the kinetic characteristics of proteolytic activity of proteases on Channa striatus protein fractions. Degree of hydrolysis (DH), amino acid composition and kinetic parameters of sarcoplasmic and myofibrillar proteins were investigated when incubated with proteinase K and thermolysin, separately. After 30 min incubation with proteases, a decrease in DH of sarcoplasmic protein was observed whereas, hydrolysis of myofibrillar protein with proteases took 2 h with an increase in DH. The major amino acids were glutamic acid (16.6%) in thermolysin- myofibrillar hydrolysate followed by aspartic acid (11.1%) in sarcoplasmic protein fraction with no enzyme treatment and lysine (10%) in thermolysin-myofibrillar hydrolysate. The apparent Michaelis constant of proteinase K was lower than thermolysin for both sarcoplasmic and myofibrillar proteins. However, rate of turnover and enzyme efficiency suggested that sarcoplasmic and myofibrillar proteins are suitable substrates for proteinase K and thermolysin hydrolytic reaction, respectively.

Matched MeSH terms: Amino Acids
Fulltext Infantile Progressive Hepatoencephalomyopathy with Combined OXPHOS Deficiency due to Mutations in the Mitochondrial Translation Elongation Factor Gene GFM1

Balasubramaniam S, Choy YS, Talib A, Norsiah MD, van den Heuvel LP, Rodenburg RJ

JIMD Rep, 2012;5:113-22.
PMID: 23430926 DOI: 10.1007/8904_2011_107

Mitochondrial disorders are a heterogeneous group of often multisystemic and early fatal diseases caused by defects in the oxidative phosphorylation (OXPHOS) system. Given the complexity and intricacy of the OXPHOS system, it is not surprising that the underlying molecular defect remains unidentified in many patients with a mitochondrial disorder. Here, we report the clinical features and diagnostic workup leading to the elucidation of the genetic basis for a combined complex I and IV OXPHOS deficiency secondary to a mitochondrial translational defect in an infant who presented with rapidly progressive liver failure, encephalomyopathy, and severe refractory lactic acidemia. Sequencing of the GFM1 gene revealed two inherited novel, heterozygous mutations: a.539delG (p.Gly180AlafsX11) in exon 4 which resulted in a frameshift mutation, and a second c.688G > A (p.Gly230Ser) mutation in exon 5. This missense mutation is likely to be pathogenic since it affects an amino acid residue that is highly conserved across species and is absent from the dbSNP and 1,000 genomes databases. Review of literature and comparison were made with previously reported cases of this recently identified mitochondrial disorder encoded by a nuclear gene. Although limited in number, nuclear gene defects causing mitochondrial translation abnormalities represent a new, rapidly expanding field of mitochondrial medicine and should potentially be considered in the diagnostic investigation of infants with progressive hepatoencephalomyopathy and combined OXPHOS disorders.

Matched MeSH terms: Amino Acids
Fulltext In vitro properties of designed antimicrobial peptides that exhibit potent antipneumococcal activity and produces synergism in combination with penicillin

Le CF, Yusof MY, Hassan H, Sekaran SD

Sci Rep, 2015;5:9761.
PMID: 25985150 DOI: 10.1038/srep09761

Antimicrobial peptides (AMPs) represent a promising class of novel antimicrobial agents owing to their potent antimicrobial activity. In this study, two lead peptides from unrelated classes of AMPs were systematically hybridized into a series of five hybrid peptides (DM1-DM5) with conserved N- and C-termini. This approach allows sequence bridging of two highly dissimilar AMPs and enables sequence-activity relationship be detailed down to single amino acid level. Presence of specific amino acids and physicochemical properties were used to describe the antipneumococcal activity of these hybrids. Results obtained suggested that cell wall and/or membrane targeting could be the principal mechanism exerted by the hybrids leading to microbial cell killing. Moreover, the pneumocidal rate was greater than penicillin (PEN). Combination treatment with both DMs and PEN produced synergism. The hybrids were also broad spectrum against multiple common clinical bacteria. Sequence analysis showed that presence of specific residues has a major role in affecting the antimicrobial and cell toxicity of the hybrids than physicochemical properties. Future studies should continue to investigate the mechanisms of actions, in vivo therapeutic potential, and improve rational peptide design based on the current strategy.

Matched MeSH terms: Amino Acids

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