title: Isolation and characterization of a tyrosinase from the skin of the white silky fowl (Gallina lanigera) employing copper saturated diethylaminoethyl-cellulose.
abstract: Tyrosinase was purified to apparent homogeneity from the skin of the White Silky fowl (Gallina lanigera). Under alkaline conditions copper ions from a complex with the diethylaminoethyl moiety of DEAE-cellulose, allowing the purification of the enzyme in a one step chromatography. In polyacrylamide gel electrophoresis containing sodium dodecyl sulfate the purified tyrosinase displays a single band with a relative molecular mass of 66,000 Da. The crystalline tyrosinase was obtained from 32-33% saturated solution of ammonium sulfate. The enzyme catalyzes the o-hydroxylation of L-tyrosine to L-dihydroxyphenylalanine as well as the oxidation of pyrocatechol to o-benzoquinone. For the pyrocatechol oxidation the Michaelis Menten constant Km, is calculated to be around 1.19 x 10(-3) M.
authors.affiliation: Shanghai Institute of Biochemistry, Academia Sinica, China.
authors.forename: H T
authors.initials: HT
authors.lastname: Wang
authors.forename: W Y
authors.initials: WY
authors.lastname: Liu
authors.forename: N
authors.initials: N
authors.lastname: Ulbrich
mesh_terms: D000818:Animals; D001717:Birds / Q000378:metabolism*; D002848:Chromatography, DEAE-Cellulose; D003300:Copper; D003460:Crystallization; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000302:isolation & purification*; D012867:Skin / Q000201:enzymology*
chemical_list: D003300:Copper; D014442:Monophenol Monooxygenase