| First Author | Halaban R | Year | 1990 |
| Journal | Proc Natl Acad Sci U S A | Volume | 87 |
| Issue | 12 | Pages | 4809-13 |
| PubMed ID | 1693779 | Mgi Jnum | J:14622 |
| Mgi Id | MGI:62786 | Doi | 10.1073/pnas.87.12.4809 |
| Citation | Halaban R, et al. (1990) Murine and human b locus pigmentation genes encode a glycoprotein (gp75) with catalase activity. Proc Natl Acad Sci U S A 87(12):4809-13 |
| abstractText | Melanogenesis is regulated in large part by tyrosinase (monophenol monooxygenase; monophenol, L-dopa:oxygen oxidoreductase, EC 1.14.18.1), 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 hypopigmented (Blt/Blt) coat versus the wild-type black (B/B). We show that the b locus codes for a glycoprotein with the activity of a catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase, EC 1.11.1.6) (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, we conclude that pigmentation is controlled not only by tyrosinase but also by a hydroperoxidase. Our 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 Blt mutation renders the protein susceptible to rapid proteolytic degradation. |
