Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.2.1.22 (cystathionine beta-synthase)
 965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The DNA sequence of a 26,677 bp fragment from the right arm of chromosome VII from Saccharomyces cerevisiae reveals 18 open reading frames (ORFs) longer than 300 bp. Eight ORFs correspond to previously characterized genes. G6620 is the 3' end of the MOL1 gene coding for a polypeptide similar to stress-inducible proteins from Fusarium; G6630 is the NAT2 gene which encodes a methionine N-acetyltransferase; G6635 is the RPL30B gene coding for the ribosomal protein L30; G6658 is RSR1 encoding a ras-related protein; G6667 is CYS4, the gene for cystathionine beta-synthase; G6670 is identical to ORF2 located close to CYS4; G6673 is PEM1/CHO2 encoding a phosphatidylethanolamine methyltransferase; G7001 is the NSR1 gene coding for a nuclear signal recognition protein. G6664 shares significant homology with the ORF YKR076w from chromosome XI. The other nine ORFs show no significant homology to any protein sequence presently available in the public data bases.
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PMID:The sequence of a 27 kb segment on the right arm of chromosome VII from Saccharomyces cerevisiae reveals MOL1, NAT2, RPL30B, RSR1, CYS4, PEM1/CHO2, NSR1 genes and ten new open reading frames. 858 25

Methionine has been shown to increase plasma cholesterol in animals. In the present study, mechanisms were investigated by which methionine could alter cholesterol metabolism. In the first experiment, forty growing rats were fed four casein-based diets differing in methionine content (2.6, 3.5, 4.5 or 6.0 g/kg) for 14 d. In the second experiment, isolated rat hepatocytes were incubated in media supplemented with 50, 100 or 200 micromol/l methionine. Dietary methionine tended to increase plasma homocysteine concentrations in the rats (P=0.058). A weak positive correlation between circulating homocysteine and plasma cholesterol was observed (R2 0.27, P<0.01). Rats fed 3.5 g/kg or more of methionine had higher concentrations of cholesterol in their plasma, in lipoprotein fractions of density (rho; kg/l) 1.006<rho<1.063 and rho>1.063, and in liver than rats fed 2.6 g/kg methionine. Rats fed 6 g/kg methionine had a higher hepatic expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase and cholesterol-7alpha-hydroxylase than rats fed less methionine. The phosphatidylcholine:phosphatidylethanolamine ratio in rat liver increased with rising dietary methionine concentration; the relative mRNA concentrations of phosphatidylethanolamine N-methyltransferase and cystathionine beta-synthase remained unaffected. Hepatocytes incubated in media supplemented with 100 or 200 micromol/l methionine had a higher cholesterol synthesis than hepatocytes incubated in a medium supplemented with 50 micromol/l methionine; the LDL uptake in hepatocytes was independent of the methionine concentration of the medium. In conclusion, the present study suggests that dietary methionine induces hypercholesterolaemia at least in part via an enhanced hepatic cholesterol synthesis.
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PMID:Effect of dietary methionine on plasma and liver cholesterol concentrations in rats and expression of hepatic genes involved in cholesterol metabolism. 1661 77

Betaine homocysteine S-methyltransferase (BHMT) catalyzes the transfer of a methyl group from betaine to homocysteine (Hcy), forming dimethylglycine and methionine. We previously showed that inhibiting BHMT in mice by intraperitoneal injection of S-(alpha-carboxybutyl)-DL-homocysteine (CBHcy) results in hyperhomocysteinemia. In the present study, CBHcy was fed to rats to determine whether it could be absorbed and cause hyperhomocysteinemia as observed in the intraperitoneal administration of the compound in mice. We hypothesized that dietary administered CBHcy will be absorbed and will result in the inhibition of BHMT and cause hyperhomocysteinemia. Rats were meal-fed every 8 hours an L-amino acid-defined diet either containing or devoid of CBHcy (5 mg per meal) for 3 days. The treatment decreased liver BHMT activity by 90% and had no effect on methionine synthase, methylenetetrahydrofolate reductase, phosphatidylethanolamine N-methyltransferase, and CTP:phosphocholine cytidylyltransferase activities. In contrast, cystathionine beta-synthase activity and immunodetectable protein decreased (56% and 26%, respectively) and glycine N-methyltransferase activity increased (52%) in CBHcy-treated rats. Liver S-adenosylmethionine levels decreased by 25% in CBHcy-treated rats, and S-adenosylhomocysteine levels did not change. Furthermore, plasma choline decreased (22%) and plasma betaine increased (15-fold) in CBHcy-treated rats. The treatment had no effect on global DNA and CpG island methylation, liver histology, and plasma markers of liver damage. We conclude that CBHcy-mediated BHMT inhibition causes an elevation in total plasma Hcy that is not normalized by the folate-dependent conversion of Hcy to methionine. Furthermore, metabolic changes caused by BHMT inhibition affect cystathionine beta-synthase and glycine N-methyltransferase activities, which further deteriorate plasma Hcy levels.
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PMID:Dietary intake of S-(alpha-carboxybutyl)-DL-homocysteine induces hyperhomocysteinemia in rats. 2079 82