Zur Darstellung und Substratspezifität einer von der Leucinamino-peptidase unterscheidbaren Aminopeptidase aus Nierenpartikeln

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Abstract
Studies are reported on the Mn2+-activation of the aminopeptidase activities for L-leucineamide and L-leucine-[beta]-naphthylamide, which are present in the cell fractions of rat kidney. It was shown that in addition to the "classical" leucine aminopeptidase, the rat kidney contains an (or several) enzyme that is especially active towards the "chromogenic substrates", i.e. arylamides of amino acids. This "particulate aminopeptidase" was purified in a 5-stage procedure from the combined mitochondria-microsome fraction of pig kidney. The enzyme shows a high activity towards the above aromatic-substituted substrates, and the highest activity towards the alanine derivates. The pH-optimum lies between 7.0 and 8.0; Co2+ -ions show a marked activation, while Mn2+and Mg2[long dash]ions have no affect or they inhibit. The cleavage of D-leucine amide is almost too low to measure.