Functional analysis of the slaty gene product (TRP2) as dopachrome tautomerase and the effect of a point mutation on its catalytic function.

Slaty (slt), an autosomal recessive mutation that arose in YZ57/Ch mice, results in the dilution of coat color and premature hair loss. Recently, a gene encoding a homologue of the melanogenic enzyme tyrosinase (termed tyrosinase related protein 2 or TRP2) was cloned and was subsequently mapped to the slaty locus on chromosome 14. TRP2 was shown to function in melanogenesis as DOPAchrome tautomerase by means of the catalytic activity of the immunopurified protein and in slaty mutant skin samples. In this study, we generated an expression vector of a murine TRP2 encoding cDNA and are able to confirm its activity as DOPAchrome tautomerase. We further demonstrate that the slaty mutation dramatically decreases the catalytic function of the protein.