Capacité de la méthionine, de la thiamine ou du pantothénate à renverser la toxicité, pour Escherichia coli, d'acides α-aminés artificiels homologues, dont la norleucine; mise en evidence du rôle probable de la méthionine dans la biosynthèse des deux vitamines
We have previously made the chemical synthesis of artificial α-amino acids substituted by one or two alkylated linear groups on the α-carbon. Our present results indicate that they have a capacity to stop the growth of E. coli 9723. When they have toxicity, the inhibition is competitively reversed by L-methionine and noncompetitively by pantothenate or thiamine; these compounds act as methionine analogues. We have concluded that the mechanism of toxicity is due in part to the repression of biosynthetic enzymes of the methionine pathway and partly to the inhibition of homoserine-O-transsuccinylase, which is the first enzyme of this pathway. We think that the consequence is an intracellular deficiency of methionine which, in turn, causes a lack of pantothenate and thiamine. Our results, therefore, indicate that methionine is necessary for the biosynthesis of pantothenate and thiamine.