The DNA (cytosine-5)-methyltransferase (m5C-MTase) M.BspRI is able to accept the methyl group from the methyl donor S-adenosyl-L-methionine (AdoMet) in the absence of DNA. Transfer of the methyl group to the enzyme is a slow reaction relative to DNA methylation. Self-methylation is dependent on the native conformation of the enzyme and is inhibited by S-adenosyl-L-homocysteine, DNA and sulfhydr...

The metabolism of the methyl group of 5-methyltetrahydrofolate was studied in rats in which cobalamin had been inactivated by exposure to nitrous oxide and in air-breathing control animals. Methylfolate labeled with [14C] in the methyl group and with [3H] in the pteridine-PABA portion was injected and the disappearance of [14C]H3- relative to [3H]folate was measured in liver. The half-time of t...

Toxic and mutagenic O6-alkylguanine adducts in DNA are repaired by O6-alkylguanine-DNA alkyltransferases (MGMT) by transfer of the alkyl group to a cysteine residue in the active site. Comparisons in silico of prokaryotes and lower eukaryotes reveal the presence of a group of proteins [alkyltransferase-like (ATL) proteins] showing amino acid sequence similarity to MGMT, but where the cysteine a...

Collisionally activated dissociation of conjugate acid ions of neopentyl isopropylamine (1) gives loss of a neutral C5H10 molecule, MH–C5H10, as the predominant decomposition peak (≥70% of the total fragment ion abundance). Quantitative evaluation of the relative peak intensities from protonated 1 and its deuterated analogues permits an assessment of the contribution of hydrogen transfer from t...

A 51 kDa fusion protein incorporating the N-methyltransferase domain of the multienzyme enniatin synthetase from Fusarium scirpi was expressed in Saccharomyces cerevisiae. The protein was purified and found to bind S-adenosyl methionine (AdoMet) as demonstrated by cross-linking experiments with (14)C-methyl-AdoMet under UV irradiation. Cofactor binding at equilibrium conditions was followed by ...

Although an enormous and still growing number of biologically diverse methyltransferases have been reported and identified, a comprehensive understanding of the enzymatic methyl transfer mechanism is still lacking. Glycine N-methyltransferase (GNMT), a member of the family that acts on small metabolites as the substrate, catalyzes methyl transfer from S-adenosyl-l-methionine (AdoMet) to glycine...

This computational and theoretical study deals with chain transfer to solvent (CTS) reactions of methyl acrylate (MA), ethyl acrylate (EA), and n-butyl acrylate (n-BA) self-initiated homopolymerization in solvents such as butanol (polar, protic), methyl ethyl ketone (MEK) (polar, aprotic), and p-xylene (nonpolar). The results indicate that abstraction of a hydrogen atom from the methylene group...

In the course of catalysis or signaling, large multimodular proteins often undergo conformational changes that reposition the modules with respect to one another. The mechanisms that direct the reorganization of modules in these proteins are of considerable importance, but distinguishing alternate conformations is a challenge. Cobalamin-dependent methionine synthase (MetH) is a 136-kDa multimod...

The synthesis of 4-methyl fentanyl, a prototype of a novel class of fentanyl analogues has been effected in 5 steps, starting from N-ethoxycarbonyl-4-piperidone (approximately 20% overall yield). In the key step, N-phenylation of secondary aliphatic amide intermediare was achieved by a novel reaction, using diphenyliodonium chloride for the phenyl group transfer. Preliminary pharmacological res...