Plasma 5-S-cysteinyldopa concentrations in oculocutaneous albinism.

5-S-cysteinyldopa concentrations were determined by high-pressure liquid chromatography and electrochemical detection in plasma from normally pigmented patients and patients with oculocutaneous albinism, both tyrosinase-positive and tyrosinase-negative. The plasma 5-S-cysteinyldopa concentrations were similar in all three groups, suggesting that 5-S-cysteinyldopa can be produced by mechanisms which do not involve tyrosinase.