S-Adenosyl Methionine-Mediated Repression of Methionine Biosynthetic Enzymes in Saccharomyces cerevisiae

AUTOR(ES)

Cherest, H.

RESUMO

S-adenosylmethionine (SAM) has been shown to provoke repression of some methionine-specific enzymes in wild-type cells, namely, adenosine triphosphate sulfurylase, sulfite reductase, and homocysteine synthetase. Repressive effects observed in SAM-supplemented cultures should be due to SAM per se, since the intracellular pool of SAM increases while the intracellular pool of methionine remains low and constant. Derepression brought about by methionine limitation is accompanied by a severe decrease in SAM as well as methionine pool sizes, although methionine adenosyl transferase is slightly derepressed. Different hypotheses have been considered to account for the previously reported implication of methionyl transfer ribonucleic acid and the presently reported SAM effects in this regulatory process.

Documentos Relacionados

• Methionine-and S-adenosyl methionine-mediated repression in a methionyl-transfer ribonucleic-acid synthetase mutant of Saccharomyces cerevisiae.
• SAM2 encodes the second methionine S-adenosyl transferase in Saccharomyces cerevisiae: physiology and regulation of both enzymes.
• S-adenosyl methionine alters the DNA contacts of the EcoKI methyltransferase.
• Methionine inhibits developmental aggregation of Myxococcus xanthus by blocking the biosynthesis of S-adenosyl methionine.
• Methionine-Mediated Repression in Saccharomyces cerevisiae: a Pleiotropic Regulatory System Involving Methionyl Transfer Ribonucleic Acid and the Product of Gene eth2