Mutations of the tyrosinase gene associated with a partial or complete loss of 
enzymatic activity are responsible for tyrosinase related oculocutaneous 
albinism (OCA1). A large number of mutations have been identified and their 
analysis has provided insight into the biology of tyrosinase and the 
pathogenesis of these different mutations. Missense mutations produce their 
effect on the activity of an enzyme by altering an amino acid at a specific 
site. The location of these mutations in the peptide can be used to indicate 
potential domains important for enzymatic activity. Missense mutations of the 
tyrosinase polypeptide cluster in four regions, suggesting that these are 
important functional domains. Two of the potential domains involve the copper 
binding sites while the others are likely involved in substrate binding. More 
critical analysis of the copper binding domain of tyrosinase can be gained by 
analyzing the structure of hemocyanin, a copper-binding protein with a high 
degree of homology to tyrosinase in the copper binding region. This analysis 
indicates a single catalytic site in tyrosinase for all enzymatic activities.