Methods for Identification and Quantification of Alkaline Phosphatase Isoenzymes in Human Serum

Abstract

Publisher Summary The tissue specific alkaline phosphatase (AP) isoenzymes found in human serum circulate free or are associated with different structures. The differentiation of AP isoenzymes has not found a wide application in the clinical chemistry laboratory. One of the reasons could be the lack of a single reliable method identifying or measuring these isoenzymes. This chapter studies the AP isoenzymes using 5 different electrophoretic and the commonly used physicochemical methods. A highly sensitive and specific assay for placental AP has been developed. Electrophoretic separation of the serum AP isoenzymes in media with large pore size and pronounced electro-osmotic flow is the most informative and simplest procedure. This technique is useful in the detection of a doublet of AP isoenzymes that are found in the serum of certain patients. This doublet consists of the soluble liver AP and the high molecular weight AP that migrates rapidly in agar and cellulose acetate. This high molecular weight AP turned out to be a plasma membrane fragment originating from the sinusoidal part of the liver cell.