[Clinical significance of alkaline phosphatase isozyme analysis]

Six bands with alkaline phosphatase (ALP) activity can be detected by electrophoresis using cellulose acetate membrane. From the anodic side, they are high molecular weight ALP (ALP1), hepatic ALP (ALP2), bone ALP (ALP3), placental ALP (ALP4), intestinal ALP (ALP5) and IgG bound ALP (ALP6). Variant ALP (ALP1) can also be detected by the use of polyacrylamide gel. Identification or quantitative measurement of each isozyme is possible by using heat inactivation, various inhibitors, gel filtration, immunoassay, etc. This report describes the method of classification of ALP isozymes, the clinical significance of each isozyme, and change in ALP isozymes in various pathological states.