Regulation of 6-methylsalicylate and patulin synthesis in Penicillium urticae

Abstract

By using selective inhibition of protein synthesis by p-fluorophenylalanine, thienylalanine, or cycloheximide, together with a resuspension technique, it is shown that 6-methylsalicylate synthetase activity of Penicillium urticae appears to be due to a metabolically stable enzyme, formed during replicatory growth, and becoming active later as a consequence of increases in substrate levels. In the same fungus, the conversion of 6-methylsalicylate into gentisaldehyde and patulin involves metabolically labile enzymes, which are formed later in the culture development. Regulation of the synthesis of these later enzymes may involve both induction in the presence of substrate and repression by high nutrient levels.