Biosynthesis of Tropolones in Penicillium Stipitatum. v. Preparation and Properties of Stipitatonic Acid Decarboxylase.

During the growth of Penicillium stipitatum, stipitatonic acid was found to be the major component of the culture medium of young cultures, whereas stipitatic acid predominated in older cultures (3). This finding, and the easy chemical decarboxylation of stipitatonic acid to stipitatic acid in boiling water, suggested that the dicarboxylic acid was the precursor of the monocarboxylic acid. Further evidence for this possibility was obtained by the preparation, from P. stipitatum mycelium, of a cell-free enzyme system, carrying out the decarboxylation of stipitatonic and puberulonic acids. The preparation, partial purification, and general properties of this decarboxylase are described in this report.