Abnormal alkaline phosphatase isoenzymes detected in the serum of elderly patients.

Alkaline phosphatase (ALP) isoenzyme analysis of 101,832 serum samples was performed by electrophoresis using cellulose acetate membrane, and abnormal bands at the alpha(1) and alpha(2) globulin positions were detected in 23 samples. The physicochemical properties of these abnormal ALP isoenzyme fractions were examined. In brief, the abnormal fractions were heat-sensitive and inhibited by L-phenylalanine, and neither sialic acid in their polysaccharide chains nor the glycosyl-phosphatidylinositol anchor was detected by the enzyme treatment. The physicochemical properties of abnormal ALP isoenzyme fractions detected in Patients 1 - 22 were similar to those of the adult small intestine type. However, the molecular weight of the adult small intestine type abnormal fractions was smaller than that of the normal fractions. These adult small intestine type abnormal bands at the alpha(1)- to alpha(2)-globulin positions, which were identified in the serum of Patients 1 - 22, were detected in elderly patients. Most of them had various basal diseases such as renal insufficiency, fracture, interstitial pneumonia, and chronic pancreatitis. Some of them had severe diseases such as rectal cancer, descending colon cancer, and septic shock. In Patient 23, the polysaccharide chain had sialic acid and was heat sensitive physicochemical properties that were similar to those of the Kasahara ALP variant.