ISOENZYMIC PATTERNS OF TYROSINASE IN THE RABBIT CHOROID AND RETINA RETINAL-PIGMENT EPITHELIUM

Tyrosinase in crude extracts from the adult rabbit choroid and retina/ retinal pigment epithelium was found to be differently affected by the inhibitors sodium metabisulfite, cyanide, diethyldithiocarbamate and 2,2'-dipyridyl: the latter inhibited the activity in the retina/retina l pigment epithelium extract after 24 hr of incubation, but not that i n the choroid. The first three inhibitors, on the other hand, inhibite d the activity in the choroid extract, but not in the retina/retinal p igment epithelium extract, after 3 hr of incubation. Both extracts con tained one insoluble and two soluble isoenzymes. The mobilities and th e apparent molecular weights of the soluble isoenzymes (more markedly so for the most rapidly migrating) differed, as revealed by polyacryla mide gel electrophoresis, resulting in distinct isoenzymic patterns. W e suggest that such patterns may be related to the characteristic mela nogenic features of the retina/retinal pigment epithelium and choroid.