The role of gamma-globulin in composition of macroamylase.

A macroamylase complex has been artificially generated by combining purified pancreatic and salivary alpha-amylase solutions with physiological amounts of human gamma-globulin. This complex was only partially dissociable at pH 3.5. Salivary alpha-amylase was shown to have higher binding affinity to gamma-globulin than the pancreatic alpha-amylase. Small amounts of macroamylase complex were also formed after the addition of purified salivary or pancreatic alpha-amylase to normal serum. This effect was more distinct when salivary alpha-amylase was added. Electrophoretic examination of serum proteins from subjects with macroamylasemia showed a significant increase of gamma-globulin fraction. Seromucoid of these subjects was also above normal range. Electrophoresis of serum glycoproteins yielded raised values of the fraction moving with gamma-globulin.