Abstract
Serum 5′ nucleotidase (NTP) was determined on 91 sera by nickel inhibition and beta-glycerophosphate substrate competition; the latter method was found to be preferable. The isoenzyme pattern of serum alkaline phosphatase (ALP) in the same 91 sera was studied by polyacrylamide gel electrophoresis and was found more helpful in patient management than serum NTP.
The serum ALP isoenzyme pattern was further studied in 50 patients with haemochromatosis. Nine out of 10 patients with clinical or radiological joint disease had a raised serum total ALP caused in half by the hepatic isoenzyme and half by the bone isoenzyme, without any clear-cut pattern. Four out of five patients with hepatoma had a raised serum total ALP due to the hepatic isoenzyme. The persistence of a high serum ALP in a patient treated actively for haemochromatosis may indicate malignant change in the liver.