Deficiency in methionine adenosyltransferase resulting in limited repressibility of methionine biosynthetic enzymes in Aspergillus nidulans
- 43 Downloads
In Aspergillus nidulans methionine can be metabolized to cysteine. Mutants blocked in this pathway were selected and divided into three groups representing three separate loci: mecA, mecB and mecC. mecC13 mutant possesses a low level of methionine adenosyltransferase and shows a limited extent of methionine-caused repression of three enzymes of the methionine biosynthetic pathway: sulfate permease, sulfite reductase and 0-acetylhomoserine sulfhydrylase. Intracellular pools of methionine do not differ markedly in the mutant and in wild type, while the S-adenosylmethionine (SAM) pool is decreased in the mutant. Methionine adenosyltransferase was found to be inducible by methionine, SAM is postulated to be involved in regulation of methionine biosynthetic enzymes in A. nidulans. Differences in regulation of methionine biosynthesis in A. nidulans, Escherichia coli and Saccharomyces cerevisiae are discussed.
KeywordsEnzyme Escherichia Coli Cysteine Methionine Aspergillus
Unable to display preview. Download preview PDF.
- Cherest, H., Surdin-Kerjan, Y., Antoniewski, J., de Robichon-Szulmajster, H.: S-adenosylmethionine mediated repression of methionine biosynthetic enzymes in Saccharomyces cerevisiae. J. Bact. (in press) (1973a)Google Scholar
- Cherest, H., Surdin-Kerjan, Y., Antoniewski, J., de Robichn-Szulmajster, H.: Effects of regulatory mutations upon methionine biosynthesis in Saccharomyces cerevisiae: loci eth2-eth3-eth10. J. Bact. (in press) (1973b)Google Scholar
- Pieniążek, N. J., Paszewski, A.: The use of media containing sodium selenate for selecting mutants of Aspergillus nidulans. Aspergillus News Letter 11, 12 (1970)Google Scholar
- Pieniążek, N. J., Stępień, P. P., Paszewski, A.: An Aspergillus nidulans mutant lacking cystathionine β-synthase: identity of L-serine sulfhydrylase with cystathionine β-synthase and its distinctness from 0-acetyl-L-serine sulfhydrylase. Biochim. biophys. Acta (Amst.) 297, 37–47 (1973)CrossRefGoogle Scholar
- Vito, P. C. de, Dreyfuss, J.: Metabolic regulation of adenosine triphosphate sulfurylase in yeast. J. Bact. 88, 1341–1348 (1964)Google Scholar