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

A disturbance of serine-glycine metabolism in a group of patients who became psychotic after oral intake of serine may be due to any serine-related enzyme abnormality. In order to elucidate this problem, we studied several enzymes in fibroblasts obtained from these patients. First, the enzyme serine hydroxymethyltransferase was investigated. The apparent Km values for serine, L-tetrahydrofolate (H4folate), and pyridoxal 5'-phosphate, as well as the maximal velocities of the forward and backward reactions measured in fibroblasts obtained from patients, were not different from those in the cells from controls. We also measured the activities of another three enzymes of the folic acid cycle, viz., 5,10-methylene-H4folate dehydrogenase, 10-formyl-H4folate synthetase, and 5,10-methenyl-H4folate cyclohydrolase, as well as the enzyme cystathionine beta-synthase. Again, no differences were found among these enzymes in fibroblasts from patients and controls. It can be concluded that the psychotic symptoms occurring after the administration of serine are not the result of any malfunctioning of the enzymes investigated.
 ...
PMID:Serine and folate metabolism in fibroblasts from episodic psychotic patients with psychedelic symptoms. 309 Oct 98

Mild hyperhomocysteinemia is a probable risk factor for atherosclerotic diseases and stroke. Recently, associations of elevated plasma homocysteine concentrations in the acute phase and of MTHFR 677 TT genotype with spontaneous cervical artery dissections (sCAD) have been reported. The purpose of this study was to test this hypothesis in the currently largest sample of patients with sCAD, taking into account known factors influencing plasma homocysteine levels. Ninety-five patients with past sCAD were compared with 95 age- and sex-matched healthy individuals. Homocysteine, vitamin B6, B12, folate, and polymorphisms of methylenetetrahydrofolate reductase (MTHFR C677T), cystathionine beta-synthase (CBS 844ins68bp) and methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase/formyltetrahydrofolate synthetase (MTHFD1 G1958A) were assessed and any associations were analysed using multivariate statistics. The occurrence of sCAD was associated with elevated homocysteine levels with an odds ratio of 1.327 per 20 % percentile. Homocysteine levels were influenced by gender, smoking status, occurrence of hypertension, vitamin B12 and folate levels, and by the MTHFR TT genotype. MTHFR, CBS 844ins68bp, and MTHFD1 G1958A genotype were not independently associated with the occurrence of sCAD. These data suggest that elevated homocysteine is associated with the occurrence of sCAD. The MTHFR C677T polymorphism is associated with the homocysteine level.
 ...
PMID:Plasma homocysteine, MTHFR C677T, CBS 844ins68bp, and MTHFD1 G1958A polymorphisms in spontaneous cervical artery dissections. 1550 5

The interconversion of folates by the one-carbon metabolism pathway is essential for the synthesis of precursors used in DNA synthesis, repair, and methylation. Perturbations in this pathway can disrupt these processes and are hypothesized to facilitate carcinogenesis. We investigated associations of 25 candidate polymorphisms in nine one-carbon metabolism genes with risk of postmenopausal breast cancer using 502 cases and 505 controls from the Cancer Prevention II Nutrition Cohort. Four single nucleotide polymorphisms (SNP) in three different genes were significantly associated with breast cancer. The nonsynonymous R134K SNP in methylenetetrahydrofolate dehydrogenase/methenyltetrahydrofolate cyclohydrolase/formyltetrahydrofolate synthase [MTHFD1; odds ratio (OR), 1.40; 95% confidence interval (95% CI), 1.06-1.85 for CT + TT] and an intronic SNP in formyltetrahydrofolate dehydrogenase (FTHFD; OR, 2.23; 95% CI, 1.09-4.54 for CC) were associated with a significant increase in risk. Significantly decreased risk was associated with an intronic SNP in FTHFD (OR, 0.75; 95% CI, 0.58-0.98 for CT + CC) and the A360A SNP in cystathionine beta-synthase (CBS; OR, 0.63; 95% CI, 0.41-0.96 for TT). The presence of at least one variant from both the methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C SNPs was also associated with increased risk (OR, 2.16; 95% CI, 1.34-3.48 for 677 CT + TT/1,298 AC + CC). Investigations into interactions of the associated SNPs with each other and with dietary factors yielded inconclusive results. Our findings indicate that genetic variation in multiple one-carbon metabolism genes may influence risk of postmenopausal breast cancer and may involve changes in methyl donor synthesis. However, larger studies are needed to further examine gene/gene and gene/diet interactions in this pathway.
 ...
PMID:Association of polymorphisms in one-carbon metabolism genes and postmenopausal breast cancer incidence. 1754 76