1. Melanosomal tyrosinase was isolated from normal C57B1 mice, and a comparison of the tyrosine-hydroxylation and dopa (3,4-dihydroxyphenylalanine)-oxidation activities of this enzyme was made. 2. The results indicate that in the absence of dopa cofactor, this enzyme is capable of tyrosine hydroxylation, but with very little subsequent dopa oxidation and melanin formation. 3. This mechanism of enzyme action may play an important role in the intracellular regulation of melanin formation. 4. Further, dopa appears to act as a positive allosteric effector for tyrosine hydroxylation by tyrosinase, in addition to its known activity as a hydrogen donor for the reaction.
Research Article|September 01 1976
Mammalian tyrosinase. A comparison of tyrosine hydroxylation and melanin formation
Biochem J (1976) 157 (3): 549-557.
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V J Hearing, T M Ekel; Mammalian tyrosinase. A comparison of tyrosine hydroxylation and melanin formation. Biochem J 1 September 1976; 157 (3): 549–557. doi: https://doi.org/10.1042/bj1570549
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