Electrophoretic amylase fractionation as an aid in diagnosis of pancreatic disease.

Six alpha-amylase (EC 3.2.1.1) isoenzymes have been resolved electrophoretically on cellulose acetate membranes in a discontinuous buffer system. The fastest migrating isoenzymes are of salivary origin (S1, S2, S3), the slower ones of pancreatic origin (P1, P2, P3). We determined the amylase isoenzyme distribution in the sera of 240 subjects. A specific pancreatic isoenzyme (P3) was observed in all clinically diagnosed cases of acute or chronic pancreatitis as well as in 15 of 40 renal-transplant patients. Moreover, P3 isoenzyme activity declined during apparent recovery from pancreatitis. The P2 isoenzyme appeared in 95% of all specimens, P1 in only 2%. The pancreatic isoenzymes were preferentially excreted in the urine of both renal-transplant patients and normal individuals. The major salivary isoenzyme, S1, was observed in 95% of all serum and urine samples; however, the S2 and S3 appeared less consistently. Our method is simple and rapid, and quite applicable for use in clinical evaluation of patients with pancreatitis or with certain nonpancreatic dysfunctions.