Effects of methionine and Cu2+ on the expression of tyrosinase activity in Streptomyces castaneoglobisporus.

Streptomyces castaneoglobisporus HUT6202 expresses an enzyme, tyrosinase, responsible for the production of melanin-like pigments. The present study revealed that the tyrosinase synthesis by the microorganism was induced about 80-fold, when young cells cultured for 6 h were incubated with methionine (Met) to the mid-log phase of growth, in comparison to without this amino acid. The Met-induced tyrosinase synthesis was inhibited by the addition of rifampicin and chloramphenicol, suggesting that transcriptional and translational events are necessary for the induction. We found that the addition of Cu2+ to the culture medium brings forward the period of expression of Met-induced tyrosinase activity.