Determination of bone alkaline phosphatase isoforms in serum by a new high-performance liquid chromatography assay in patients with metabolic bone disease

Abstract

Four human gene loci are encoding for the alkaline phosphatase [orthophosphoric-monoester phospho-hydrolase (alkaline optimum)]; EC 3.1.3.1, (ALP) isoenzymes; “tissue non-specific”, placental, germ cell and small intestinal locus (Fishman 1990). ALP from the “tissue non-specific” locus is expressed in tissues such as bone, liver and kidney. Different carbohydrate side-chains or maybe remaining fragments of the in situ cell membrane glycosyl-phosphatidyl-inositol anchor, or both, yields “tissue specific” structures in the ALP isoforms from this gene locus (Moss 1992). In accordance with strict isoenzyme definition, bone and liver ALP should be referred to as isoforms of the same isoenzyme.