Two new methods for separating and quantifying bone and liver alkaline phosphatase isoenzymes in plasma.

Abstract

We describe two new methods for the separation and quantification of the bone and liver isoenzymes of alkaline phosphatase (EC 3.1.3.1) in plasma. In the first, we use wheat-germ lectin to precipitate the bone isoenzyme. About 80% of this, but minimal liver isoenzyme, is precipitated. The activity of the bone isoenzyme is calculated from measuring the alkaline phosphatase activity in the precipitate, that of liver alkaline phosphatase by subtracting the activity of the bone isoenzyme from total alkaline phosphatase activity. The liver fraction will also contain biliary, intestinal, and placental alkaline phosphatase if these are present in the original plasma, but correction for such activity is readily made. In the second method, samples are separated on cellulose acetate membranes that, before electrophoresis, have been soaked in buffer containing wheat-germ lectin. The bone isoenzyme is retarded and clearly separated from the liver fraction, allowing these isoenzymes to be quantified by densitometry. Both methods are rapid, reproducible, and suitable for use in the diagnostic laboratory.

Bone turnover and bone mineral density in patients with congenital adrenal hyperplasia

“…The overall intra and interassay coefficients of variation were 3 and 5%, respectively. Serum activity of BAP was measured by wheat germ lectin assay (Rosalki & Foo, 1984) with intra and inter-assay coefficients of variation of 3 and 5%, respectively. Serum activity of TRAP was measured by enzyme activity assay (De La Piedra et al, 1989) with intra and inter-assay coefficients of variation of 2 and 4%, respectively.…”

Bone alkaline phosphatase and collagen markers as early predictors of height velocity response to growth‐promoting treatments in short normal children

“…4% at 240 and 506 U/l respectively. ALP isoenzymes were quantified using a modification in agarose gel (Crofton, 1992) of a well established wheat germ lectin affinity electrophoresis method (Rosalki & Foo, 1984). The reference range of the bone isoform in children using our method was 180-700 U/l and its interassay coefficients of variation (in plasma from children without liver or bone disease) were 2 .…”

The Effect of Pregnancy on Bone Density and Bone Turnover

“…Wheat germ lectin precipitates out the bone but not the placental or liver isoenzyme in this assay. (24) The carboxy (PICP) and amino (PINP) terminal propeptides of type I procollagen were measured using RIA, (25,26) CV 3% for PICP and 2% for intact PINP (Orion Diagnostica, Oulu, Finland). Serum intact osteocalcin was measured by IRMA, ELSA-OST-NAT, CV 6%, with the limit of detection of 0.4 µg/liter.…”