• Journal of Life Science
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• v.21 no.1
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• pp.96-101
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• 2011

S-Adenosyl-L-methionine synthtase (SAM-s) catalyzes the biosynthesis of SAM from ATP and L-methionine. SAM plays important roles in the primary and secondary metabolism of cells. A metK encoding a SAM-s was searched from Streptomyces natalensis producing natamycin, a predominantly a strong antifungal agent, inhibiting the growth of both yeasts and molds and preventing the formation of aflatoxin in filamentous fungi. To obtain the metK of S. natalensis, PCR using primers designed from the two highly conserved regions for metK genes of Streptomyces strains was carried out, and an intact 1.2-kb metK gene of S. natalensis was cloned by genomic Southern hybridization with PCR product as a probe. To identify the function of the cloned metK gene, it was inserted into pSET152ET for its high expression in the Streptomyces strain, and then introduced into S. lividans TK24 as a host by transconjugation using E. coli ET12567(pUZ8002). The high expression of metK in S. lividans TK24 induced actinorhodin production on R5 solid medium, and its amount in R4 liquid medium was 10-fold higher than that by exconjugant including only pSET152ET.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.5
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• pp.659-664
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• 2012

The present experiment aimed to evaluate the effect of HMBi on the production performance and metabolism in dairy cows. Thirty multiparous Holstein dairy cows under similar conditions were randomly assigned to three dietary treatments; i) Control, a basal diet; ii) T1, a basal diet plus HMBi (0 g prepartum and 18 g postpartum); and iii) T2, a basal diet plus HMBi (10 g prepartum and 18 g postpartum). Treatments were initiated 21 d before expected calving and continued through 91 d postpartum. HMBi was top-dressed onto the total mixed ration of each cow. Treatments did not affect dry matter intake, plasma urea nitrogen, peak milk yield, days to peak milk yield, nonesterified fatty acid, glutamate pyruvate transaminase, glutamic oxalaetic transaminase, milk fat content, milk protein content, milk lactose content, and milk solid non-fat content. The milk composition yields were increased by the HMBi-supplemented treatment. The T1 and T2 treatments increased the yields of 4% fat-corrected milk yield, milk fat, milk protein, and milk lactose compared with the control. Although there was no difference in the milk composition of the control and T2-treated cows, the T2-treated cows exhibited higher milk fat yield (increased by 74 g/d), lower milk urea nitrogen (reduced by 3.41%), and plasma ${\beta}$-hydroxy butyrate than the control cows. The results indicate that HMBi supplementation to diet has beneficial effects, and that there is no difference between supplementation at prepartum and starting only at parturition.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.3
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• pp.107-111
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• 2019

Objective: Spermatogenesis is a complex process that is regulated by a number of genes, some of which are involved in folate-dependent 1-carbon metabolism. Methionine synthase (encoded by MTR) is a key enzyme participating in this pathway. This study aimed to investigate the relationship of the MTR 2756A > G polymorphism with idiopathic male fertility in the Iranian population. Methods: The participants of this study included 100 men with idiopathic infertility and 100 healthy men as the control group. Genotyping of MTR 2756A > G was performed using the polymerase chain reaction and restriction fragment length polymorphism technique. The obtained data were analyzed using SPSS ver. 20.0 with a level of confidence of p< 0.05. Results: The frequencies of the A and G alleles at this locus were 77% and 23% in infertile patients and 84% and 16% in the control group, respectively. The frequencies of the GG, GA, and AA genotypes were 5%, 36%, and 59% in the infertile patients versus 3%, 27%, and 70% in the control group, respectively. No significant difference was observed in any genetic models. Conclusion: In general, the findings of this study suggest that the MTR 2756A > G single-nucleotide polymorphism is not a predisposing factor for idiopathic infertility in men.

• Toxicological Research
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• v.24 no.4
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• pp.281-287
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• 2008

Impairment of hepatic metabolism of sulfur-containing amino acids has been known to be linked with induction of liver injury. We determined the early changes in the transsulfuration reactions in liver of rats challenged with a toxic dose of $CCl_4$ (2 mmol/kg, ip). Both hepatic methionine concentration and methionine adenosyltransferase activity were increased, but S-adenosylmethionine level did not change. Hepatic cysteine was increased significantly from 4 h after $CCl_4$ treatment. Glutathione (GSH) concentration in liver was elevated in $4{\sim}8$ h and then returned to normal in accordance with the changes in glutamate cysteine ligase activity. Cysteine dioxygenase activity and hypotaurine concentration were also elevated from 4 h after the treatment. However, plasma GSH concentration was increased progressively, reaching a level at least several fold greater than normal in 24 h. ${\gamma}$-Glutamyltransferase activity in kidney or liver was not altered by $CCl_4$, suggesting that the increase in plasma GSH could not be attributed to a failure of GSH cycling. The results indicate that acute liver injury induced by $CCl_4$ is accompanied with extensive alterations in the metabolomics of sulfurcontaining amino acids and related substances. The major metabolites and products of the transsulfuration pathway, including methionine, cysteine, hypotaurine, and GSH, are all increased in liver and plasma. The physiological significance of the change in the metabolomics of sulfur-containing substances and its role in the induction of liver injury need to be explored in future studies.

• Journal of Nutrition and Health
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• v.15 no.2
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• pp.119-128
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• 1982

The effect of dietary protein on growth and lipid levels of plasma and liver was studied in weanling male rats fed diets differing protein sources and amino acid balance. Rats were devided into 9 experimental diets which were grouped into 3 categories ; 1) Simple protein category includes gluten-, soy protein isolate-, and casein-containing diet groups, 2) Supplemented category includes casein supplemented with methionine, soy protein isolate supplemented with methionine, and gluten supplemented with lysine and methionine, 3) Mixed protein category includes diet groups containing gluten (2/3), casein (1/3), soy protein isolate (2/3) and casein (1/3), and casein (1/3), soy protein isolate (1/3) and gluten (1/3). The experimental diets composed of 15% protein, 65.8% carbohydrate, 10% fat and 1% cholesterol. The body wt. gain and P.E.R. were greater in rats of supplemented and mixed protein groups than simple protein groups. No statistical differences were found in plasma cholesterol among gluten, soy protein isolate and casein groups. Consumption of diets supplemented with limiting amino acid to gluten or soy protein isolate reduced the plasma cholesterol level by 23.2% and 34.2% respectively. However there was no difference between casein and the supplemented casein groups. The mixed protein groups shows relatively high plasma cholesterol concentration and low liver cholesterol levels. On the other hand gluten group showed low plasma cholesterol and high liver cholesterol levels, which means body cholesterol pool may not have been changed by the dietary protein. Feeding soy protein meal and the supplemented soy protein isolate resulted in lower plasma cholesterol, plasma triglycerides, liver cholesterol and liver triglycerides levels. This hypolipidemic effect is considered to see unique to soy protein isolate. Rats in gluten and the supplemented gluten groups showed lower plasma protein levels and a tendency of fatty liver.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.8
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• pp.1013-1021
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• 2010

This study was conducted to determine the effects of amino acid-enriched ruminally protected fatty acid (AARPFA) on plasma fatty acids and amino acids, growth performance and carcass characteristics of Korean native steers (Hanwoo) by simultaneous supply of fatty acids and limiting amino acids (methionine and lysine). Eighteen finishing Hanwoo steers, 18 months of age and weighing an average of $459.0{\pm}38.9\;kg$, were used for studies of the metabolism of plasma fatty acids and amino acids during supplementation of AARPFA. Also, 45 finishing Hanwoo steers, 16 months of age and weighing an average of $408.6{\pm}26.5\;kg$, were used for growth performance and carcass characteristics during supplemention of AARPFA. There were three treatments which comprised a basal diet supplemented with AARPFA at 0 g (T1), 50 g (T2) or 100 g (T3), respectively. Concentrations of saturated, unsaturated and total fatty acids in plasma were increased in T3 compared with other treatments (p<0.05). Concentrations of methionine and lysine in plasma were linearly increased with increasing levels of AARPFA (p<0.01). Average daily gain, dry matter intake and feed conversion ratio were not different among the treatments. Marbling score measured by ultra-sound scanning was higher in T3 than in T1 at 24 months of age (p<0.05). Rib eye area, back fat thickness, yield index and yield grade score were similar across the treatments. Marbling score and quality grade score were higher in T3 compared with other treatments (p<0.01). Thus, plasma fatty acids, methionine and lysine metabolism were affected by supplementing with 100 g of AARPFA which also had positive effects on marbling score and meat quality grade of finishing Hanwoo steers.

• Journal of Ginseng Research
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• v.40 no.2
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• pp.113-120
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• 2016

Background: The present study aimed to compare the relative abundance of proteins and amino acid metabolites to explore the mechanisms underlying the difference between wild and cultivated ginseng (Panax ginseng Meyer) at the amino acid level. Methods: Two-dimensional polyacrylamide gel electrophoresis and isobaric tags for relative and absolute quantitation were used to identify the differential abundance of proteins between wild and cultivated ginseng. Total amino acids in wild and cultivated ginseng were compared using an automated amino acid analyzer. The activities of amino acid metabolism-related enzymes and the contents of intermediate metabolites between wild and cultivated ginseng were measured using enzyme-linked immunosorbent assay and spectrophotometric methods. Results: Our results showed that the contents of 14 types of amino acids were higher in wild ginseng compared with cultivated ginseng. The amino acid metabolism-related enzymes and their derivatives, such as glutamate decarboxylase and S-adenosylmethionine, all had high levels of accumulation in wild ginseng. The accumulation of sulfur amino acid synthesis-related proteins, such as methionine synthase, was also higher in wild ginseng. In addition, glycolysis and tricarboxylic acid cycle-related enzymes as well as their intermediates had high levels of accumulation in wild ginseng. Conclusion: This study elucidates the differences in amino acids between wild and cultivated ginseng. These results will provide a reference for further studies on the medicinal functions of wild ginseng.

• Environmental Analysis Health and Toxicology
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• v.22 no.2 s.57
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• pp.165-170
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• 2007

Elevation of homocysteine levels is a risk factor for cardiovascular diseases and liver diseases. It has been reported that both streptozotocin-induced type I diabetic rats and obese type II diabetic rats have plasma total homocysteine lower than each control rats. We determined the effects of lean type II diabetes on homocysteine levels using type 2 diabetic Goto-Kakizaki rats. The concentrations of serum glucose were increased to ${\sim}two-fold$ of control levels and the total cholesterol levels were also increased in GK rats. Hepatic aspartate, histidine, threonine, alanine and methionine levels were significantly increased in GK rats. Plasma aspartate and glutamate levels were elevated, but threonine and arginine levels were decreased in GK rats. Plasma total homocysteine levels were not changed in GK rats, but hepatic total homocysteine levels were increased to ${\sim}three-fold$ of control levels. These results suggest that hepatic metabolism of sulfur-amino acid may be altered in diabetic condition.

• Journal of Plant Biology
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• v.31 no.4
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• pp.277-288
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• 1988

The effects of ammonium ion and glutamate on CO2 fixation abilities and related carbon metabolism were investigated in pea (Pisum sativum L. cv. Sparkle) leaf discs under conditions favoring photorespiration (21% O2, 0.03% CO2) and nonphotorespiration (5% O2, 0.03% CO2). A concentration of more than 10 mM of NH4+ decreased the photosynthetic CO2 fixation and those inhibitory effects were more remarkable in 21% O2 than in 5% O2 conditions. The effect of glutamate on CO2 fixation was found to be independent of the O2 level, as glutamate increased the CO2 fixation under both 21% and 5% O2 conditions. L-methionine-dl-sulfoximine, an irreversible inhibitor of glutamate synthetase, however, inhibited the CO2 fixation markedly under 21% O2, but did not affect it under 5% O2 conditions. The treatment with NH4+ elevated the relative amounts of 14C incorporated into soluble components from 14CO2 with no relation to O2 levels, while glutamate increased 14C into insoluble components and neutral sugars. Glutamate, especially, seemed to stmulate the biosynthesis of starch under 5% O2 condition. These results indicated that NH4+ stimulated the degradation of sugar or starch and this proposal was confirmed by the increasing of pyruvate kinase activity in leaf discs treated with ammonium ion.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.16 no.1
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• pp.1-9
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• 2016

Newborn screening (NBS) is important if early intervention is effective in a disorder and if there are sensitive and specific biochemical markers to detect disorder. Methionine is a useful marker to detect abnormal methionine-homocysteine metabolism, especially homocystinuria which needs urgent medical intervention. However, hypermethioninemia could occur in other metabolic disorder including liver disease, tyrosinemia type I, methionine adenosyltransferase (MAT) I/III deficiency, glycine N-methyltransferase (GNMT) deficiency, or adenosylhomocysteine hydrolase deficiency. However, experience with NBS for homocystinurias and methylation disorders is limited. Especially, MAT I/III deficiency which is the most common cause of persistent hypermethioninemia have two inheritance, autosomal recessive (AR) and autosomal dominant (AD), and their clinical manifestation is different between AR and AD. Here, author reviewed recent articles of guideline and proposed guideline for homocystinuria and methylation disorder.