ZONE ELECTROPHORETIC STUDIES OF SERUM ALKALINE PHOSPHATASE*†

Abstract

A zone electrophoretic study was made of sera of increased alkaline phosphatase activity, including 25 cases of obstructive or infiltrative hepatobiliary disease (group A), 10 cases of hepatocellular disease (group B), and 16 cases of hyperphosphatasemic bone disease (group C); 12 normophosphatasemic subjects served as controls (group D). Electrophoresis was done in starch blocks, and p-nitrophenylphosphate, pH 10.3, served as phosphatase substrate; phosphatase and protein patterns were compared. In every case the major zone of alkaline phosphatase activity was in the alpha-2 globulin region and in some cases, particularly those of group A, a 2d zone of activity corresponding to the alpha-1 globulins was present. The alpha-1 alkaline phosphatase accounted for 16.2% (average) of the total activity in cases of group A, and for only 3.5, 2.2, and 1.8% of the activity in groups B, C and D respectively. Two distinct phosphatase peaks were noted in 88% of the cases of group A, while in only 16% of the cases in the combined groups B, C and D were 2 peaks noted. The alpha-2 and alpha-1 phosphatases were similar in pH optimum, cyanide sensitivity and fluoride insensitivity. An appreciable fraction of the alkaline phosphatase of bile had mobility similar to the alpha-1 globulins of serum.