[Formation of high-molecular aggregates between serum amylase and colloidal plasma substitutes (author's transl)]

The distribution of molecular weights of human serum amylase was studied by gel filtration of serum, obtained before and after infusion of the colloidal plasma substitutes hydroxyethyl starch, dextran and gelatin, respectively. Both in serum, drawn after intravenous infusion of hydroxyethyl starch, and in a solution of hydroxyethyl starch with serum we observed a significant increase in the molecular weight of serum amylase. The occurrence of this "macroamylase" may be explained by the formation of aggregates between hydroxyethyl starch and amylase. Because of its high molecular weight the elimination of this, presumably, enzyme-substrate-complex is retarded, thus leading to the observed increase of serum amylase activity. In contrast to these observations concerning hydroxyethyl starch no change in the apparent molecular weight of serum amylase was observed following the infusion of either gelatin or dextran or their solutions with serum.