Localization of Serum Leucine Aminopeptidase Activity by Paper Electrophoresis

Abstract

The electrophoretic behavior of serum leucine aminopeptidase (LAP) in normal individuals, in pregnancy, and in patients with hepatobiliary disease was investigated with paper electrophoresis technics. In normal serum LAP migrated as a single component in the [alpha]1-globulin fraction. In patients with elevated serum LAP activity due to hepatobiliary or pancreatic disease supplementary peaks of enzymatic activity were demonstrable in other protein fractions. In early pregnancy the electrophoretic pattern of LAP was similar to that observed in normal serum, whereas during the third trimester LAP activity was demonstrable only in the [alpha]2-globulin. The paper electrophoresis patterns of serum LAP appear to be of limited diagnostic usefulness and in jaundiced sera were largely related to the presence or absence of activity in the albumin, [beta]-globulin or at the origin.