NovP is an S-adenosyl-l-methionine-dependent O-methyltransferase that catalyzes the penultimate step in the biosynthesis of the aminocoumarin antibiotic novobiocin. Specifically, it methylates at 4-OH of the noviose moiety, and the resultant methoxy group is important for the potency of the mature antibiotic: previous crystallographic studies have shown that this group interacts directly with t...

Pre-steady state partitioning analysis of the HhaI DNA methyltransferase directly demonstrates the catalytic competence of the enzyme.DNA complex and the lack of catalytic competence of the enzyme.S-adenosyl-L-methionine (AdoMet) complex. The enzyme.AdoMet complex does form, albeit with a 50-fold decrease in affinity compared with the ternary enzyme.AdoMet.DNA complex. These findings reconcile ...

OBJECTIVES We investigated whether lowering of fasting homocysteine concentrations, either with folic acid or with betaine supplementation, differentially affects vascular function, a surrogate marker for risk of cardiovascular disease, in healthy volunteers. As yet, it remains uncertain whether a high concentration of homocysteine itself or whether a low folate status--its main determinant--is...

UNLABELLED S-Adenosyl-L-homocysteine, the product of S-adenosyl-L-methionine (SAM) methyltransferases, is known to be a strong feedback inhibitor of these enzymes. A hydrolase specific for S-adenosyl-L-homocysteine produces L-homocysteine, which is remethylated to methionine and can be used to regenerate SAM. Here, we show that the annotated S-adenosyl-L-homocysteine hydrolase in Methanocaldoco...

In B(12) deficiency, inadequate DNA synthesis seems due in large measure to a block of tetrahydrofolic acid (THFA) regeneration from 5-methyl THFA (via homocysteine transmethylation). In support of the above, homocysteine appears to facilitate and methionine to reduce de novo DNA synthesis. This was measured by the ability of deoxyuridine to suppress thymidine-(3)H uptake into DNA in human bone...

A novel sulfobetaine block copolymer, poly(N-(morpholino)ethyl methacrylate)-b-poly(4-(2-sulfoethyl)-1-(4-vinylbenzyl)pyridinium betaine) (PMEMA-b-PSVBP), was synthesized via reversible addition-fragmentation chain transfer polymerization. In aqueous solution, PMEMA homopolymer becomes insoluble in the presence of Na2SO4 (>0.6 M), whereas PSVBP homopolymer molecularly dissolves in the presence ...

In our previous work with rats, plasma and tissue homocysteine concentrations were decreased by selenium deprivation. The purpose of this study was to follow up and expand on that work by determining the effects of selenium status (deficient, adequate, and supranutritional) on several aspects of homocysteine metabolism involving methionine recycling and transsulfuration. A 2nd objective was to ...

BACKGROUND The last 30 years have seen an exponential increase in metaanalyses. By combining multiple studies, metaanalysis can provide an overview of the totality of evidence on a particular question and the statistical power needed to reduce random error and produce precise estimates of even modest effect sizes. This capability is of particular value when many small studies address similar qu...

The present study was undertaken to investigate a possible involvement of phospholipid methyltransferases in the coupling of receptor-mediated stimulation to secretion. Phospholipid methyltransferases were assayed in isolated parotid acini in the presence of carbamoylcholine or isoprenaline. Carbamoylcholine reduced the incorporation of methyl groups into phospholipids, whereas isoprenaline sho...

Kinetic and binding studies involving a model DNA cytosine-5-methyltransferase, M.HhaI, and a 37-mer DNA duplex containing a single hemimethylated target site were applied to characterize intermediates on the reaction pathway. Stopped-flow fluorescence studies reveal that cofactor S-adenosyl-l-methionine (AdoMet) and product S-adenosyl-l-homocysteine (AdoHcy) form similar rapidly reversible bin...