Quantification of skeletal alkaline phosphatase in osteoporotic serum by wheat germ agglutinin precipitation, heat inactivation, and a two-site immunoradiometric assay.
Three methods for quantifying skeletal alkaline phosphatase (ALP; EC 3.1.3.1) activity/immunoactivity in serum--heat inactivation, wheat germ agglutinin (WGA) precipitation, and an immunoradiometric assay--were tested for recovery and specificity and applied to 81 sera collected from 14 postmenopausal osteoporotic subjects. The heat-inactivation and WGA precipitation assays showed relative recoveries of 91-100% and 16-32%, respectively, for skeletal ALP with complete specificity (no cross-reactivity with hepatic or intestinal ALP); the IRMA showed a relative recovery of 86-100% and 11-14% cross-reactivity with hepatic ALP. There was a closer correlation between the heat-inactivation assay and IRMA (r = 0.833) than between the WGA precipitation assay and IRMA (r = 0.673) or between the heat-inactivation and WGA-precipitation assays (r = 0.568). The WGA precipitation assay failed to detect skeletal ALP in three serum samples that contained significant amounts as determined by the heat-inactivation assay and the IRMA.
Farley
J R
JR
Department of Medicine, Loma Linda University, CA 92357.
Hall
S L
SL
Ilacas
D
D
Orcutt
C
C
Miller
B E
BE
Hill
C S
CS
Baylink
D J
DJ
D000469:Alkaline Phosphatase / Q000097:blood* / Q000276:immunology; D001842:Bone and Bones / Q000201:enzymology*; D003429:Cross Reactions; D004789:Enzyme Activation; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007527:Isoenzymes / Q000097:blood* / Q000276:immunology; D010024:Osteoporosis / Q000097:blood / Q000201:enzymology*; D011233:Precipitin Tests; D011863:Radioimmunoassay / Q000379:methods; D014909:Wheat Germ Agglutinins
D007527:Isoenzymes; D014909:Wheat Germ Agglutinins; D000469:Alkaline Phosphatase