Gamma-glutamyl transpeptidase in the pigment cells of rhesus eyes.
We demonstrated that gamma-glutamyl transpeptidase, one of the enzymes of the gamma-glutamyl cycle, is present in the melanocytes of the eyes of rhesus macaques. Enzyme activity was detected in active melaninsynthesizing melanocytes of the iris stoma and in fetal and neonatal retinal pigment epithelium. It was not detected in adults retinal pigment epithelium or choroidal melanocytes, which are ontogenetically more advanced in development and have little melanogenic activity. Our data show that gamma-glutamyl transpeptidase activity correlates well with growth, early differentiation, and active melanogenesis, and support the hypothesis that in addition to tyrosinase, a second enzyme, such as gamma-glutamyl transpeptidase, takes part in the melanin and pheomelanin metabolic pathways.
D000818:Animals; D002829:Choroid / Q000201:enzymology; D002924:Ciliary Body / Q000201:enzymology; D005123:Eye / Q000196:embryology / Q000201:enzymology*; D005333:Fetus / Q000201:enzymology; D008253:Macaca mulatta; D008544:Melanocytes / Q000201:enzymology*; D010857:Pigment Epithelium of Eye / Q000201:enzymology; D012160:Retina / Q000201:enzymology; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
D005723:gamma-Glutamyltransferase