Acid phosphatase in melanosome formation: a cytochemical study in normal human melanocytes.
A cytochemical study of acid phosphatase (AcPase) activity was conducted in normal epidermal melanocytes from both sun-exposed and sun-protected human skin to define the relationship between enzyme activity and melanosome formation. In the perikarya of melanocytes of both sun-exposed and sun-protected skin, it was determined that only a small proportion of stage 1 and 2 melanosomes had AcPase activity (20-33% and 9-26%, respectively). The proportion of AcPase-positive melanosomes in perikarya increased in stage 3 (39-56%), reaching a maximum in stage 4 (67-84%). In the dendrite of melanocytes, where melanosomes were mostly in stages 3 and 4, the vast majority of melanosomes demonstrated AcPase activity (79-87% and 88-93%, respectively). The preferential incorporation of AcPase in the later stages of melanogenesis is more consistent with a possible role for this enzyme in the degradation or transfer of melanosomes, rather than as an essential component in the early process of melanization.
D000135:Acid Phosphatase / Q000378:metabolism*; D000328:Adult; D001415:Back; D001706:Biopsy; D002081:Buttocks; D004817:Epidermis / Q000201:enzymology; D006651:Histocytochemistry; D006801:Humans; D008247:Lysosomes / Q000201:enzymology; D008543:Melanins / Q000096:biosynthesis; D008544:Melanocytes / Q000201:enzymology*; D013472:Sunlight
D008543:Melanins; D000135:Acid Phosphatase