CONVERSION OF VERSICONAL ACETATE TO VERSICONAL AND VERSICOLORIN-C IN EXTRACTS FROM ASPERGILLUS-PARASITICUS

The primary product of hydrolysis of versiconal acetate catalyzed by porcine liver esterase and the 35-70% ammonium sulfate fraction from a soluble extract from mycelia of Aspergillus parasiticus was versiconal. Versiconal was stable at neutral pH for several hours and was rapidly converted to versi-colorin C by treatment with 0.4 M HCl. The addition of NADPH to the 35-70% ammonium sulfate fraction resulted in conversion of versiconal acetate to both versiconal and versicolorin C. The conversion of versiconal acetate to versicolorin C in the cell-free system is proposed to involve an esterase and an NADPH-dependent cyclase. © 1990 Kluwer Academic Publishers.