Regulation of repressible alkaline phosphatase by organic acids and metal ions in Neurospora crassa

Abstract

Various organic acids used in standing cultures of Neurospora regulate the specific activity of mycelial, repressible alkaline phosphatase. The evidence suggests that the regulatory control occurs primarily through chelation of metal ions which are necessary for the production or stability of the enzyme. Both iron and zinc were needed in the growth medium to produce a maximum enzyme level, while a high copper concentration depressed the enzyme level. Electrophoresis of mycelial extracts on gradient polyacrylamide gels demonstrated that the organic acids and iron do not have these regulatory effects on the repressible or constitutive acid phosphatases of Neurospora.