Acid Phosphatase Isoenzymes in Human Skin Fibroblasts (37768)

Five isoenzymes of acid phosphatase activity were detected by polyacryla-mide gel electrophoresis in cultivated human fibroblasts. All of the isoenzymes were present in the lysosomal subcellular fraction, while a single anionic isoenzyme was detected in the microsomal subcellular fraction. The anionic isoenzymes tended to be firmly membrane bound and were solubilized by treatment with Triton X-100. Red cell acid phosphatase isoenzymes were studied using starch gel electrophoresis. An isoenzyme formerly considered to be unique to the red blood cell was detected in leukocytes and in cultivated human fibroblasts.