Biochemical identification and ganglionic localization of leech angiotensin-converting enzymes.
We demonstrate the presence of a membrane and soluble form of leech Theromyzon tessulatum angiotensin-converting enzyme (ACE). Four steps in the purification of this enzyme include gel-permeation, captopril-sepharose affinity and anion-exchange chromatography followed by a reverse-phase HPLC. The peptidyl dipeptidases (of approximately 120 and approximately 100 kDa) are glycosylated enzymes hydrolysing the Phe8-His9 bond of angiotensin I, exhibiting the same specific activity and Km whereas the soluble ACE exhibits a higher catalytic efficiency. This hydrolysis is inhibited by the ACE-specific antagonist captopril. Western blot analysis of a polyclonal antiserum raised against the first 11 amino-acid residues of the membrane ACE and the N-terminal sequence of the soluble molecule also demonstrates the presence of two ACE enzymes. Anti-ACE immunocytochemistry also supports the presence of two forms of ACE. This material is found in neurons and glia. We demonstrate for the first time the cellular localization and biochemical characterization of ACEs in the central nervous system of an invertebrate. Thus, the leech brain may represent a simple model for the study of these enzymes.
Vandenbulcke
F
F
Centre de Biologie Cellulaire, Laboratoire de Phylogénie Moléculaire des Annélides, EA DRED 1027, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Laurent
V
V
Verger-Bocquet
M
M
Stefano
G B
GB
Salzet
M
M
D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D002216:Captopril / Q000494:pharmacology; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000201:enzymology*; D007150:Immunohistochemistry; D007700:Kinetics; D007865:Leeches / Q000201:enzymology*; D016253:Microscopy, Immunoelectron; D009412:Nerve Fibers / Q000201:enzymology / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology / Q000201:enzymology*; D007703:Peptidyl-Dipeptidase A / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*
D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril; D007703:Peptidyl-Dipeptidase A