A Bacillus subtilis methyltransferase capable of methylating membrane-bound methyl-accepting chemotaxis proteins (MCPs) of a chemotaxis mutant was purified to homogeneity. MCPs are normally unmethylated in this strain. Results of gel filtration chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicate that the enzyme is a 30,000 molecular weight monomer. The nzym...

Cantoni (1) has demonstrated that the requirement for adenosine triphosphate in the synthesis in vitro of creatine and N’methylnicotinamide from methionine and guanidoacetic acid and nicotinamide, respectively, is due to the formation of S-adenosylmethionine from methionine and ATP,’ the compound being the direct donor of its methyl group to the respective acceptors. As far as we are aware, no ...

The mechanism of action of low dose methotrexate in rheumatoid arthritis has not been established. It has been shown to have an anti-inflammatory effect and to inhibit neutrophil chemotaxis, but the effect on monocytes has not been widely studied. Normal donor peripheral blood monocytes were incubated with methotrexate in vitro and their superoxide production, chemotaxis, and phagocytosis subse...

Four cDNAs for spermidine synthase (SPDS), which converts the diamine putrescine to the higher polyamine spermidine using decarboxylated S-adenosylmethionine as the co-factor, were isolated from Nicotiana sylvestris, Hyoscyamus niger, and Arabidopsis thaliana. When the N.sylvestris SPDS cDNA was expressed in a SPDS-deficient E. coli mutant, the recombinant protein showed high SPDS activity, but...

Rats received intracisternal [(3)H]norepinephrine and, after 5 min, intraperitoneal L-dopa (100 mg/kg); they were killed at intervals during the subsequent 24 hr. Their brains were assayed for norepinephrine, L-dopa, S-adenosylmethionine, and [(3)H]norepinephrine and its metabolites. Rats that received L-dopa had markedly lower brain concentrations of S-adenosylmethionine and of O-methylated me...

An amino acid-defined, folate-deficient diet was used to investigate the regulation of pancreatic glycine N-methyltransferase in vivo. This enzyme modulates the ratio of S-adenosylmethionine to S-adenosylhomocysteine and is inhibited by bound folate in vitro. Rats were fed either a folate-deficient diet, a folate-supplemented diet (pair-fed to the deficient group), or a folate supplemented diet...

Three pathways for phosphatidylcholine synthesis were assayed in castor bean (Ricinus communis var. Hale) endosperm. Phosphatidylethanolamine: S-adenosylmethionine methyl transferase occurred predominantly in the endoplasmic reticulum fraction, but some activity appeared in the mitochondria. Phosphorylcholine glyceride transferase occurred exclusively in the endoplasmic reticulum. The phosphory...

dcAdoMet (decarboxylated S-adenosylmethionine) is an essential intermediate in the synthesis of polyamines. Its content is normally very low, amounting to less than 5% of that of S-adenosylmethionine itself. It was found that in mice lacking spermine synthase there was a large increase in dcAdoMet and that overexpression of spermine synthase reduced the amount of this nucleoside. There was also...

Adenosine dialdehyde and nitrous oxide, specific S-adeno-sylhomocysteine hydrolase and methionine synthetase inhibitors, respectively, induced differentiation of the human promyelocytic cell line HL-60. Their effect did not appear to be mediated through changes in transmethylation or decreased S-adenosylmethionine synthesis because (1) there was little correlation between the concentrations of ...