Normal serum alkaline phosphatase isoenzymes examined by acrylamide and starch gel electrophoresis and by isoenzyme analysis using organ-specific inhibitors.

The serum alkaline phosphatase isoenzymes of 56 normal individuals have been studied from three points of view: the partition of intestinal type alkaline phosphatase from nonintestinal by L-phenylalanine inhibition and their respective heat sensitivities; the performance of starch gel electrophoresis; and acrylamide gel electrophoresis of all sera. The improved acrylamide gel electrophoresis technic did separate bone and liver isoenzymes more effectively than starch gel electrophoresis. The liver position of every subject was seen as the fastest moving compact band and had relatively low heat inactivation, whereas the bone band was slower, less compact, and had a high heat inactivation. The intestinal position was easily observed on starch gel electrophoresis, and was visualized on acrylamide gel by the subsequent use of the liver and bone inhibitor, L-homoarginine, in the substrate medium. These results show the heterogeneity of alkaline phosphatase isoenzymes in the serum of the normal individual.