The Enzymatic α-N-Methylation of Histidine
1970; Elsevier BV; Volume: 245; Issue: 22 Linguagem: Inglês
10.1016/s0021-9258(18)62649-3
ISSN1083-351X
AutoresYoshinori Ishikawa, Donald B. Melville,
Tópico(s)GABA and Rice Research
ResumoCell-free extracts of Neurospora crassa catalyze the methylation of the α-amino nitrogen atom of histidine, α-N-methylhistidine, and α-N,N-dimethylhistidine to form hercynine (α-N,N,N-trimethylhistidine). S-Adenosylmethionine serves as the common methyl group donor. The enzyme system responsible for these methylations has been purified 500-fold by DEAE-cellulose chromatography, ammonium sulfate fractionation, gel filtration, and DEAE-Sephadex chromatography. The most highly purified preparation showed a single major component during acrylamide gel electrophoresis. Fractionation studies, kinetic studies, inhibition studies, and heat-inactivation studies all indicate that a single enzyme (histidine-α-N-methyltransferase) is responsible for the three transmethylation reactions involved in the conversion of histidine to hercynine.
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