ANALYSIS OF TYROSINASE SYNTHESIS IN STREPTOMYCES-ANTIBIOTICUS

S-35-labelling experiments and Western blot analysis were used to investigate methionine induction of tyrosinase synthesis in Streptomyces antibioticus. De novo synthesis of the enzyme occurred as a function of time and methionine concentration. Induction appeared to be relatively specific for methionine and closely related analogues. Under the conditions used, the enzyme was secreted rapidly, with little intracellular accumulation. Upon induction in the absence of Cu2+, apotyrosinase was synthesized at 70% of the level in control cultures provided with the cation. Inhibitor studies showed that both transcriptional and translational events are required for tyrosinase induction. Deletions in the ORF 438 region of the mel operon suggest that this sequence has a role in the phenotypic expression of tyrosinase.