Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.10.3.1 (tyrosinase)
 9,065 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A number of chromogenic Streptomyces, producing diffusible melanoid pigment on complex organic media, fail to form melanin pigment on conventionally used synthetic tyrosine agar. By means of our new melanin formation test, almost all the chromogenic streptomyces can now be detected in chemically defined medium. In contrast to ordinary chromogenic streptomyces, two streptomyces species of the International Streptomyces Project, S. griseus ISP 5236 and S. ornatus ISP 5307, produce melanin pigment only on synthetic tyrosine agar, without showing chromogenicity on complex organic media. From the results obtained with S. griseus ISP 5236 and S. phaeochromogenes ISP 5073, it was revealed that melanin formation by Streptomyces, in general, is inhibited by L-cysteine present in organic nitrogen sources incorporated into natural media. Most chromogenic species of streptomyces produce a higher level of tyrosinase and rapidly utilize L-cysteine in the culture media which result in the manifestation of good chromogenicity on natural media. Peculiarity of chromogenicity of S. griseus and S. ornatus might be due to the lower ability to produce tyrosinase and to utilize L-cysteine in the culture medium.
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PMID:Chromogenesis mirabilis in Streptomyces griseus. 462 4

The culture of Streptomyces galbus ISP-5089 has a yellow-green colour caused by the accumulation of actinomycin X when it is grown in synthetic media at 28 degrees C; the colour turns dark-brown at 42 degrees C due to the synthesis of melanoid pigments. The population composition does not undergo any noticeable changes in that case, an no specific melanin-synthesizing mutants appear as a result of autoselection . The biosynthesis of actinomycin X (at 28 degrees C) and melanoid pigments (at 42 degrees C) is regulated by temperature. At 42 degrees C, L-DOPA oxidase is synthesized and laccase is activated; these two enzymes are involved in the synthesis of melanoid pigments. The organism does not has tyrosinase. The synthesis of melanoid pigments, when the mesophilic culture of S. galbus ISP-5089 is grown in the regime of superoptimal temperatures (42 to 47 degrees C), may be considered as a protective ecological reaction of the organism to unfavourable conditions of the environment.
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PMID:[Nature of the brown pigment and the composition of the phenol oxidases of Streptomyces galbus]. 620 87