Cloning and identification of a novel tyrosinase and its overexpression in Streptomyces kathirae SC-1 for enhancing melanin production.

A 30-kDa novel tyrosinase was purified to homogeneity. The Km for L-Dopa and L-tyrosine were determined as 0.42 and 0.25 mM. The 1231 bp (base pair) melC gene and its 167 bp promoter Pskmel were obtained by thermal asymmetric interlaced polymerase chain reaction based on the amino acids fragment obtained from MS results of the purified enzyme. The protein sequence of tyrosinase shows maximum identity (84%) to tyrosinase from Streptomyces galbus. The melC was introduced into S. kathirae. The melanin production and the transcriptional level of melC in recombinant S. kathirae [pIJPskmelmelC] were about 2.1-fold and 2-fold higher than the wild-type strain, respectively. The melanin concentration was maximized at 28.8 g L(-1).