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Endopeptidase‐24.11 and aminopeptidase activity in brain synaptic membranes are jointly responsible for the hydrolysis of cholecystokinin octapeptide (CCK‐8)
Author(s) -
Matsas Rebecca,
Turner Anthony J.,
Kenny A.John
Publication year - 1984
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(84)80583-9
Subject(s) - phosphoramidon , chemistry , endopeptidase , hydrolysis , neprilysin , biochemistry , aminopeptidase , membrane , enzyme , stereochemistry , amino acid , leucine
Endopeptidase‐24.11 (EC 3.4.24.11) from pig kidney hydrolysed CCK‐8 (sulphated) at two distinct sites: Asp‐Tyr(SO 3 H)‐Met‐Gly↓Trp‐Met‐Asp↓PheNH 2 . Under initial conditions, the splitting of the Asp 7 ‐Phe 8 NH 2 bond proceeded 4‐times more rapidly than the Gly 4 ‐Trp 5 bond. Pig brain striatal synaptic membranes attacked this substrate at the same sites and this activity was inhibited by phosphoramidon. However, other products were detected even in the presence of phosphoramidon. One of these products was identified as free tryptophan. Since their formation was inhibited by bestatin, one or more membrane aminopeptidases is also implicated in the degradation of CCK‐8.