title: Purification and isoelectric heterogeneity of chicken tyrosinase.
abstract: Tyrosinase (EC 1.14.18.1) was purified from regenerating chicken feathers. Most of the enzyme activity was in the insoluble fraction, which was solubilized with 0.5% sodium cholate. Solubilized tyrosinase showed multiple forms on isoelectric focusing. The isoelectric points had the following pI values: 5.06, 4.83, 4.68, 4.56, 4.44, 4.32, 4.24, 4.14, 4.06 and 3.97. This tyrosinase fraction was subjected to trypsin (EC 3.4.21.4) cleavage, Sephacryl S-200, hydroxylapatite and DEAE-cellulose chromatography. Purified enzymatically active tyrosinase also showed multiple forms. Their isoelectric points were: 4.23, 4.14, 4.06, 3.99 and 3.91. Each active form had almost the same molecular weight, estimated at 66 000. Staining for 1,2-diol groups of glycoproteins and neuraminidase (EC 3.2.1.18) treatment suggested that chicken tyrosinase is a glycoprotein. The enzyme showed both dopa(L-3,4-dihydroxylphenylalanine) oxidase activity and tyrosine hydroxylase activity.
mesh_terms: D000818:Animals; D004156:Catechol Oxidase / Q000302:isolation & purification*; D002645:Chickens; D005241:Feathers; D007526:Isoelectric Point; D008970:Molecular Weight; D014442:Monophenol Monooxygenase / Q000302:isolation & purification*; D009439:Neuraminidase; D014357:Trypsin
chemical_list: D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase; D009439:Neuraminidase; D014357:Trypsin