title: Analysis of tyrosinases as asparagin-linked oligosaccharides by concanavalin A lectin chromatography: appearance of new segment of tyrosinases in melanoma cells following interrupted melanogenesis induced by glycosylation inhibitors.
abstract: The structural alteration of carbohydrate moieties of tyrosinases associated with the depigmentation process induced by glycosylation inhibition has been investigated by using concanavalin A (Con A) affinity chromatography. Con A affinity chromatography of deoxycholate-solubilized large and small granule fractions shows that while all tyrosinases found in control B-16 cells exhibit affinity to Con A lectin, there is an emergence on non-Con A binding tyrosinases in the unpigmented cells induced by glycosylation inhibitors, such as tunicamycin and glucosamine. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis, control tyrosinase activity forms 2 distinct bands consisting of T1 and T3. But tyrosinases from the unpigmented cells lose T3 tyrosinase and are resolved into a few different molecular weight components, one of which is Con A affinitive T1 tyrosinase and the others are non-Con A affinitive tyrosinases with smaller molecular weights than the T1 tyrosinase. These findings suggest that altered structures of carbohydrate moiety in tyrosinase molecules play a role in the induction of loss of membrane-binding capacity of tyrosinases, resulting in the loss of melanization in pigment cells.
mesh_terms: D000818:Animals; D002241:Carbohydrates / Q000096:biosynthesis; D004156:Catechol Oxidase / Q000032:analysis*; D002846:Chromatography, Affinity; D003208:Concanavalin A / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D008543:Melanins / Q000096:biosynthesis; D008545:Melanoma / Q000032:analysis*; D051379:Mice; D014442:Monophenol Monooxygenase / Q000032:analysis*; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: D002241:Carbohydrates; D008543:Melanins; D003208:Concanavalin A; D014415:Tunicamycin; D003513:Cycloheximide; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase