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The Regulation of Arginine Metabolism in Saccharomyces cerevisiae: Exclusion Mechanisms

par Wiame, Jean-Marie
Référence Current topics in cellular regulation, 4, C, page (1-38)
Publication Publié, 1971-01

Article révisé par les pairs

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Résumé :

This chapter discusses arginine biosynthesis and degradation in Saccharomyces cerevisiae (S. cerevisiae). S. cerevisiae is able to make its own arginine from ammonium as sole nitrogen source. This implies the transfer of NH4 + into glutamate, which is transformed into ornithine; NH4 + is transferred into glutamine, which is the donor of NH3 for carbamyl phosphate synthesis. Aspartate is the donor of the fourth nitrogen atom of the arginine molecule. Arginine can be used as the only nitrogen nutrient; under these conditions, arginine is degraded by arginase into ornithine and urea, the δ-nitrogen of ornithine is transferred to glutamate by δ-L-ornithine transaminase, and the α-nitrogen appears in glutamate by the dehydrogenation of the pyrroline carboxylate resulting from the cyclization of glutamic semi-aldehyde, the second product of transamination. Biosynthesis and degradation offer a typical case of concurrent pathways, which have to be regulated in opposite way. © 1971, ACADEMIC PRESS, INC.