Determination of alkaline phosphatase isoenzymes and isoforms in dog serum by a simple anion exchange chromatographic method

摘要

The well-known marker of bone formation is bone alkaline phosphatase, which is produced by osteo-blasts and is required for osteoid formation and matrix mineralization. Alkaline phosphatase (ALP, EC 3.1.3.1) is a zinc-containing glycoprotein enzyme catalyzing the hydrolysis of phosphomonoesters at alkaline pHs. ALP is synthesized in a variety of tissues and has different isoenzymes and isoforms. Four variants of ALP have been identified in domestic animals: bone ALP, intestinal ALP, liver ALP, and, in dogs, corticosteroid-induced ALP. Efforts have been made to develop analytical techniques that can differentiate between the different isoenzymes of ALP in animals. These methods include heat inactivation, gel electrophoresis, precipitation with wheat-germ lectin, and, recently, radioimmunoassay and enzyme-linked immuno-sorbent assay. We developed a simple, fast, and less expensive chromatographic method for differential determination of ALP isoenzymes and isoforms in serum samples. Three peaks of ALP activity were identified in chromatographic fractions. These were related to bone, liver, and steroid isoenzymes of ALP.