Glycylprolyl beta-naphthylamidase activity in human serum.

Glycylprolyl beta-naphthylamidase activities in sera from 40 normal subjects (18-81 years) were: 22.6 +/- 0.9 (S.E.) (11.8-38.2) I.U./1 serum at 37 degrees C. The enzyme activities did not differ significantly with age between the younger group under 40-years-old and the older group over 40-years-old. Males, especially under 40-years-old, had slight but significantly higher activities than females. The levels were decreased in patients with gastric cancer. The levels were elevated in patients with hepatobiliary diseases, and had significant correlations with the results of the serum tests in hepatic diseases such as glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, alkaline phosphatase and total bilirubin, but had no correlation with serum lactate dehydrogenase. In cellulose acetate electrophoresis, normal sera had a single peak at the beta-globulin region, but the sera in hepatitis or liver cirrhosis showed not only an increase in the normal peak at the beta-globulin region but also the appearance of the other one or two new peaks in the alpha1 and alpha2-globulin regions.