Transcription of the tyrosinase gene in Streptomyces michiganensis DSM 40015 is induced by copper and repressed by ammonium

Abstract

Induction of tyrosinase activity in the actinomycin producer Streptomyces michiganensis requires a medium low in ammonium and rich in copper ions. Copper is not only an essential part of the tyrosinase enzyme but it is also required for the induction of the gene at the level of transcription. Addition of copper, effective in both young and old cultures, specifically induces tyrosinase, which under optimal conditions may become the major newly synthesized protein. Ammonium represses tyrosinase formation at the level of transcription. Once repressed, tyrosinase biosynthesis cannot be induced by copper.

Analysis of tyrosinase synthesis in Streptomyces antibioticus

“…Although Cu2+ is essential for the synthesis of catalytically active enzyme, apotyrosinase is synthesized at appreciable levels (70% of control) upon induction in the absence of the copper. In contrast to the previous results with S. michiganensis (Held & Kutzner, 1990), induction of tyrosinase synthesis with Cuz+ in the absence of methionine was not observed. In addition to its role as an activator of apotyrosinase, Cu2+ may stabilize the protein; this could account for the enhanced enzyme activity seen when Cuz+ was provided to cultures of S. michiganensis.…”

Partial purification and characterisation of two actinomycete tyrosinases and their application in cross-linking reactions

“…Optimal production of tyrosinase was found to occur in the complex medium, MPPM, a medium typically used in the production of bioactive secondary metabolites [15]. In addition, similar to other streptomycete strains [23], the addition of CuSO 4 .5H 2 O to the medium resulted in the induction of tyrosinase production in both strains, while the addition of L-methionine had a limited effect (data not shown).…”

“…Similarly, Ikeda et al [24] showed that L-methionine induces production of tyrosinase in S. antibioticus, S. glaucescens and S. castaneoglobisporus, but not in Streptomyces michiganensis, where Cu 2+ was found to induce tyrosinase production [23]. The addition of Cu 2+ and glucose to the S. antibioticus culture medium has also been found to enhance the production of tyrosinase [25].…”

“…It is therefore not surprising, that melanin production and tyrosinase induction has been demonstrated in various studies. Held and Kutzner [23] showed that tyrosinase production in S.…”

Thermocrispum gen. nov., a New Genus of the Order Actinomycetales, and Description of Thermocrispum municipale sp. nov. and Thermocrispum agreste sp. nov.

“…Formation of melanin was determined on complex peptone-yeast extract-iron agar (58) and on a synthetic agar medium containing CuS04 with and without tyrosine (19). The following physiological tests were performed by using previously described methods: resistance to lysozyme (35); nitrate reduction (26); hydrolysis of esculin, arbutin, urea, and allantoin with final concentrations of P-glycosides, urea, and allantoin of 0.1, 1, and 1%, respectively (34); hydrolysis of colloidal chitin (20) and pectin (66); lipolysis of Tween 80 (17); lipolysis of tributyrin, as well as degradation of poly-P-hydroxybutyric acid and xylan (23); and lecithinase activity (egg yolk reaction) and hemolysis (26).…”