Serum Leucine Aminopeptidase Assay Using a Dialysis Membrane-Covered Glassy-Carbon Electrode

Abstract

The activity of leucine aminopeptidase in serum was determined by measuring the increase over a given time period in current due to the oxidation of 5-aminosalicylic acid as enzymatically released from leucine-3-carboxy-4-hydroxyanilide using a dialysis membrane-covered glassy-carbon electrode. The activities determined amperometrically using this method for eighteen serum samples were in excellent agreement with those determined using a colorimetric method with leucine-p-nitroanilide as a substrate (correlation coefficient between the two sets of results, 0.998).