The mechanism of formation de novo of the methyl group of methionine has been studied in mammalian, avian, and bacterial cell-free systems (l-8). The studies on extracts of various mutant strains of Escherichia coli have shown that, of the common compounds, formaldehyde or the P-carbon atom of serine is the best precursor of the methyl of methionine (5-7). Optimal formation of methionine from s...

Thymidylate synthetase was purified about 600to 800-fold from 7-day chick embryo and was found to methylate uridine 5’-phosphate at 40% the rate of deoxyuridine 5’-phosphate. The pH optima and salt effects on the two reactions di!Tered, but most of the evidence indicated that the same enzyme was responsible for both activities. The K,,, for deoxyuridine 5’-phosphate was 102to 103-fold lower tha...

BACKGROUND AND OBJECTIVES Women undergoing assisted reproductive procedures, such as in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), fail to achieve pregnancy in approximately 70% of cases. Postulating that among the possible causes of failure of embryo implantation might be an impairment of the uteroplacental circulation due to hypercoagulability in the mother, we inv...

We investigated the association between 12 single nucleotide polymorphisms (SNPs) in 11 genes involved in folate metabolic and preterm birth. A subset of SNPs selected from 11 genes/loci involved in the folic acid metabolism pathway were subjected to SNaPshot analysis in a case-control study. Twelve SNPs (CBS-C699T, DHFR-c594+59del19, GST01-C428T, MTHFD-G1958A, MTHFR-C677T, MTHFR-A1298C, MTR-A2...

In serine cycle methylotrophs, methylene tetrahydrofolate (H4F) is the entry point of reduced one-carbon compounds into the serine cycle for carbon assimilation during methylotrophic metabolism. In these bacteria, two routes are possible for generating methylene H4F from formaldehyde during methylotrophic growth: one involving the reaction of formaldehyde with H4F to generate methylene H4F and ...

1. Twenty-four Sprague-Dawley female rats were randomly assigned to three groups (groups A, B, C). Group A was given a folic acid-free diet and groups B and C received 0.0018 g folic acid/kg diet. Rats in group C were also given a supplement of 1 mg folic acid/d by intraperitoneal injection. 2. After 14 d of feeding the rats were mated. The diets were continued throughout gestation. On day 21, ...

10-Formyltetrahydrofolate dehydrogenase (EC 1.5.1.6) is a bifunctional enzyme, displaying both NADP(+)-dependent dehydrogenase activity for the formation of tetrahydrofolate and CO2, and NADP(+)-independent hydrolase activity for the formation of tetrahydrofolate and formate. A previous report [Case, Kaisaki and Steele (1988) J. Biol. Chem. 263, 1024-1027] claimed that dehydrogenase and hydrola...

PURPOSE The aim of this case-control study was to investigate the relationship between homocysteine (tHcy), 5,10 methylene tetrahydrofolate reductase (MTHFR) C677T genotype, folate and vitamin B12 status, and retinal vein occlusion (RVO). METHODS Subjects with RVO (n = 106) were recruited from outpatient and inpatient sources. Controls (n = 98) were selected to achieve a similar age and sex d...