Non-homogeneity of serum leucine arylamidase (LAP) activity in hepatocellular and obstructive jaundice.

In 40 patients with hepatocellular and obstructive jaundice and in 20 healthy subjects the pattern of serum leucine arylamidase (LAP) isoenzymes was determined. Polyacrylamide gel electrophoresis was used for demonstration of enzyme non-homogeneity. It was found that the main enzyme activity in healthy subjects was connected with postalbumins. In some healthy subjects and additional zone of activity was observed in beta lipoproteins. Only exceptionally 3- and 4-fraction enzymograms were found in healthy subjects. Additional activity zones were present in these subjects in the alpha2 macroglobulin region or in the region of slowly migrating haptoglobins. In hepatocellular jaundice, i.e. in viral hepatitis, the total serum LAP activity increased slightly. In the enzymogram this increase was localized in the postalbumin fraction and caused also appearance of additional, sporadically occurring isoenzymes migrating with rapidly moving haptoglobins. In obstructive jaundice of benign or malignant etiology the total serum enzyme activity rose strikingly. In most patients a 6-fraction enzymogram was found. The activity of postalbumin isoenzyme was particularly increased, while no changes were observed in the remaining activity zones sporadically occurring in healthy subjects and in hepatocellular jaundice.