Many but not all species of Streptomyces species harbour a bicistronic melC operon. in which melC2 encodes an extracellular tyrosinase (a polyphenol oxidase) and melC1 encodes a helper protein. On the other hand. a melC-homologous operon (melD) is present in all sequenced Streptomyces chromosomes and could be isolated by PCR from six other species tested. https://cuttingedgecutleryco.shop/product-category/sword/