monophenol monooxygenase

(redirected from monophenol oxidase)

mon·o·phe·nol mon·o·ox·y·gen·ase

(mon-ō-fē'nol mon'ō-oksĭ-jen-ās'),
1. A copper-containing oxidoreductase that catalyzes the oxidation of o-diphenols to o-quinones by O2, with the incorporation of one of the two oxygen atoms in the product; it also catalyzes the oxidation of monophenols, such as l-tyrosine, to dihydroxy-l-phenylalanine (dopa), a precursor of melanin and epinephrine (catecholamines), and can act as a catechol oxidase; a deficiency of this enzyme is observed in several forms of albinism. Synonym(s): cresolase, monophenol oxidase, tyrosinase
2. Synonym(s): laccase

monophenol monooxygenase

/mono·phe·nol mono·oxy·gen·ase/ (-fe´nol mon″o-ok´sĭ-jen″ās) any of a group of oxidoreductases that catalyze a step in the formation of melanin pigments from tyrosine.


A gene on chromosome 11q14-q21 that encodes tyrosinase, a copper-containing oxidase involved in pigment (e.g., melanin) formation and metabolism of other polyphenolic compounds. Tyrosinase catalyses the rate-limiting conversions of tyrosine to DOPA, DOPA to DOPA-quinone.

Molecular pathology
TYR mutations cause oculocutaneous albinism types 1A and 1B.