Methionine is a sulfur-containing amino acid that is reversibly converted into homocysteine. Homocysteine is an independent cardiovascular risk factor frequently associated with the insulin resistance syndrome. The effects of insulin on methionine and homocysteine kinetics in vivo are not known. Six middle-aged male volunteers were infused with L-[methyl-2H3,1-13C]methionine before (for 3 h) an...

Methionine aminopeptidase (MetAP) catalyzes removal of the initiator methionine from nascent polypeptides. In eukaryotes, there are two forms of MetAP, type 1 and type 2, whose combined activities are essential, but whose relative intracellular roles are unclear. Methionine metabolism is an important aspect of cellular physiology, involved in oxidative stress, methylation, and cell cycle. Due t...

Metabolism of L-[1-14C]methionine, DL-[1-14C]methionine and DL-[1-14C]2-hydroxy-4-methylthiobutanoic acid (DL-HMB) by broiler chicks which had been fasted overnight or given a methionine-deficient diet was compared with fed (control) birds. The excretion of 14C-labelled material, total 14CO2 exhaled, 14C incorporation into tissue proteins and the 14C-labelled material in perchloric-acid-soluble...

AIM Non-alcoholic steatohepatitis (NASH) is a globally recognized liver disease. A methionine- and choline-deficient diet is used to induce NASH in mice; however, this diet also causes severe body weight loss. To resolve this issue, we examined the effects of methionine content in a high-fat and choline-deficient (HFCD) diet on body weight and the development of NASH in mice. METHODS C57BL/6J...

Methionine given parenterally to rats caused rapid disappearance of methyltetrahydrofolate from the liver and a corresponding rise in tetrahydrofolate and formyl-tetrahydrofolate concentrations. When [14C]H3--H4folate was given, methionine caused an increased [14C]0(2) excretion, indicating that oxidation of the methyl group had occurred. Methionine was more effective than S-adenosylmethionine ...

The inability of the methionine requiring Escherichia coli mutant (1-344) to grow in methionine free media containing inorganic sulfur, cystine, or homocystine has been demonstrated (Lampen et al., 1947). While methionine has been shown to be essential for growth, the metabolism of nonmethionine sulfur added to media containing methionine has not been investigated directly. In the results repor...

The objective of this study was to evaluate the effect of dietary supplementation of antibacterial peptide and zinc methionine on performance and some serum biochemical parameters of weaned piglets. Rongchang male piglets (28 days of age, initial weight 8.4 ± 0.65 kg) were used. All piglets were randomly allotted to four diets including the control group, the antibacterial peptide (AP) group co...

Mutants of Chlorella sorokiniana selected for resistance to the methionine analogue ethionine took up ethionine at the same rate as did the wild type strain. Cells of two ethionine-resistant mutants produced severalfold higher levels of free methionine and cysteine than did wild type cells.Exogenous methionine had no apparent effect on free methionine production in a mutant that produces excess...

Intact methionine residues in proteins were rapidly and precisely determined by measuring methyl thiocyanate released during the reaction with CNBr and separated by g.l.c. Conditions for the reaction and for chromatography on columns of Porapak P-S are described. The recovery of methyl thiocyanate from several methionine derivatives and analogues were examined. Carbamoylmethionine was adopted a...

The hyperhomocysteinemia induced by a dietary addition of 1% methionine was significantly suppressed by the concurrent addition of 1% glycine or 1.4% serine to the same degree. The methionine-induced increase in the hepatic concentration of methionine metabolites was significantly suppressed by glycine and serine, but the hepatic cystathionine beta-synthase activity was not enhanced by these am...