monophenol monooxygenase

(redirected from cresolase)

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
Farlex Partner Medical Dictionary © Farlex 2012


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.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
References in periodicals archive ?
In the presence of molecular oxygen, this enzyme catalyzes hydroxylation of monophenols to o-diphenols (cresolase activity) and their subsequent oxidation to o-quinones (catecholase activity).
Tyrosinase (EC is a copper-containing monooxygenase catalyzing the o-hydroxylation of monophenols to the corresponding catechols (monophenolase or cresolase activity) and the oxidation of monophenols to the corresponding o-quinones (diphenolase or catecholase activity).
Furthermore, the membrane bound enzyme from the eastern oyster is unable to oxidize most monophenols (cresolase activity) (Table 1).