STUDIES ON MACROAMYLASEMIA WITH SPECIAL REFERENCE TO THE COMPONENTS BOUND TO AMYLASE AND FOLLOW-UP OF THE CLINICAL COURSE

Abstract

Four cases of macroamylasemia were reported and the components bound to amylase were studied. The macroamylase in 3 of 4 cases were electrophoretically in β-globulinn region and their amylase activity was blocked by anti-IgA antibody, which suggested that macroamylase in these 3 cases war IgA-binding type. The molecular size of these macroamylase was between 7S and 19S which was dissociated to normal size after they were chromatographed by low pH at 3.4. In the remaining one case, the serum amylase was 7S macroamylase and the electrophoretic mobility was in γ-globulin region. The treatment by low pH at 3.4 failed to develope normal amylase in molecular size in this case. These characters of this peculiar macroamylase resembled to those of glycogen-binding amylase. However, neuraminidase treatment of this macroamylase did not show almost any change in electophoretic mobility in contrast to glycogen-binding amylase. Furthermore, no adsorption of amylase in this case was observed in Con-A chromatography which retained considerable amounts of glycogen-binding amylase. Immunoelectrophoretic studies revealed that the components bound to amylase in this case were albumin and α--lipoprotein. The proportion of macroamylase to normal amylase in these four cases have varied considerably during follow-up period. The etiology of this fluctuation remains to be elucidated in future studies.