Lysine Inhibition of in vivo Homocitrate Synthesis in Penicillium chrysogenum

Summary: A lysine bradytroph of Penicillium chrysogenum Wis. 54–1255 was isolated. The mutant (l1) grew with α-aminoadipic acid and excreted homocitrate. In vivo accumulation of homocitrate, which did not require protein synthesis, was markedly reduced by lysine. These results indicate that lysine diminution of penicillin production is caused by feedback inhibition of homocitrate synthase, thus limiting the supply of α-aminoadipic acid available for penicillin biosynthesis.