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Cholecystokinin octa- and tetrapeptide degradation by synaptic membranes. III. Inactivation of CCK-8 by a phosphoramidon-sensitive endopeptidase

par Deschodt Lanckman, Monique ;Koulischer, Denis;Przedborski, Serge ;Lauwereys, Marc
Référence Peptides, 5, 3, page (649-651)
Publication Publié, 1984

Article révisé par les pairs

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Résumé :

Solubilization of rat synaptic membranes by Triton X-100 followed by DEAE-cellulose chromatography allowed the separation of a phosphoramidon-sensitive endopeptidase that cleaved CCK-8. This enzymatic activity revealed similar if not identical to 'enkephalinase A'. A major cleavage point, at the Trp30-Met31 bond, and a minor one at the Tyr27-Met28 bond were identified in the sequence of CCK-8. Replacements of the Met28 and Met31 residues by Thr and either Leu or Nle, respectively, in CCK-9 analogues, did not improve the resistance of these peptides to enzymatic degradation. The regional distribution in rat brain of this CCK-8 cleaving endopeptidase displayed marked variations with the highest activity in striatal membranes; it closely followed that described for 'enkephalinase' in mouse brain.