Murine and human b locus pigmentation genes encode a glycoprotein (gp75) with catalase activity
- Yale Univ. School of Medicine, New Haven, CT (USA)
Melanogenesis is regulated in large part by tyrosinase, and defective tyrosinase leads to albinism. The mechanisms for other pigmentation determinants (e.g., those operative in tyrosinase-positive albinism and in murine coat-color mutants) are not yet known. One murine pigmentation gene, the brown (b) locus, when mutated leads to a brown (b/b) or hypopigmentated (B{sup lt}/B{sup lt}) coat versus the wild-type black (B/B). The authors show that the b locus codes for a glycoprotein with the activity of a catalase (catalase B). Only the c locus protein is a tyrosinase. Because peroxides may be by-products of melanogenic activity and hydrogen peroxide in particular is known to destroy melanin precursors and melanin, they conclude that pigmentation is controlled not only by tyrosinase but also by a hydroperoxidase. The studies indicate that catalase B is identical with gp75, a known human melanosomal glycoprotein; that the b mutation is in a heme-associated domain; and that the B{sup lt} mutation renders the protein susceptible to rapid proteolytic degradation.
- OSTI ID:
- 6249964
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America; (USA), Vol. 87:12; ISSN 0027-8424
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CATALASE
ENZYME ACTIVITY
MELANIN
HEREDITARY DISEASES
TYROSINASE
GENE MUTATIONS
ANTIBODIES
GENES
MAN
MICE
PIGMENTS
ANIMALS
DISEASES
ENZYMES
HYDROXY COMPOUNDS
HYDROXYLASES
MAMMALS
MUTATIONS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDOREDUCTASES
PEROXIDASES
PRIMATES
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques