Acid Phosphatase Activity in Melanosomes

In 1965, Seiji and Iwashita (1) found acid phophatase and adenosine triphosphatase, in addition to tyrosinase, the enzyme responsible for melanin formation, in a melanosome fraction isolated by density gradient centrifugation from Harding-Passey mouse melanoma. The biological significance and origin of these two enzymes have not yet been clarified. In this paper, the origin of acid phosphatase activity is studied.