[Neutral leucinamidasic activity of human serum. Semiautomatic method of analysis].
Half automated method for determining a L-leucinamide splitting enzymatic activity in human sera. In normal and pathological human sera, two distinct L-leucinamide splitting enzymatic activities have been demonstrated. One of them has an optimal activity at pH 9 (alcaline leucine amidase activity) and shows the most properties of a classic leucinaminopeptidase (E.C. 3.4.11.1). The other (neutral leucine amidase activity) has an optimal activity at pH : 7,5--7,8 and is not activated by Mg2+ ions. In the present work a semi-automated method permitting the determination of the "neutral leucine amidase activity" is presented. The mean of the reference values for normal human sera are established to 31,54 mUI/ml, and the upper normal limit is 48 mUI/ml. The neutral leucine amidase activity is studied in pathological sera comparatively with two other aminopeptidase activities : "alcaline leucine amidase activity", and "leucine-arylamidase". Our study shows that in pathological sera, the neutral leucine amidase activity" varies often without any correlation with those parameters.
D001322:Autoanalysis / Q000379:methods; D004789:Enzyme Activation; D005069:Evaluation Studies as Topic; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007931:Leucyl Aminopeptidase / Q000097:blood*; D008274:Magnesium / Q000494:pharmacology; D012016:Reference Values; D013696:Temperature; D013997:Time Factors
D007931:Leucyl Aminopeptidase; D008274:Magnesium
L'activité leucinamidasique neutre du sérum humain. Méthode de dosage semi-automatique.