title: Self-proteolysis regulation in the Bothrops jararaca venom: the metallopeptidases and their intrinsic peptidic inhibitor.
abstract: Snake venom proteome variation is a well-documented phenomenon, whereas peptidome variation is still relatively unknown. We used a biological approach to explore the inhibitory activities present in the whole venom of Bothrops jararaca that prevents the venom self-proteolysis and/or digestion of the glandular tissue. Although snake venom metallopeptidases have long been known from the biochemical up to the clinical point of view, the mechanisms by which these enzymes are regulated in the reptile's venom gland remain fairly unknown. We have successfully demonstrated that there are three synergistic weak inhibitory mechanisms that are present in the crude venom that are able to abolish the metallopeptidase activity in situ, namely: (i) citrate calcium chelation; (ii) acidic pH and; (iii) enzymatic competitive inhibition by the tripeptide Pyroglutamyl-lysyl-tryptophan. Taken together, these three factors become a strong set-up that inhibits the crude venom metallopeptidase activity as well as a purified metallopeptidase from this same venom. However, this inhibition can be totally reverted by dilution into an optimal pH solution, such as the blood.
authors.affiliation: CAT/CEPID, Instituto Butantan, Av Vital Brasil, 1500, São Paulo - SP, 05503-900, Brazil.
authors.forename: Rafael
authors.initials: R
authors.lastname: Marques-Porto
authors.forename: Ivo
authors.initials: I
authors.lastname: Lebrun
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Pimenta
mesh_terms: D000818:Animals; D017837:Bothrops; D002122:Calcium Chloride / Q000737:chemistry; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003435:Crotalid Venoms / Q000737:chemistry* / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000378:metabolism; D008666:Metalloendopeptidases / Q000737:chemistry; D045726:Metalloproteases / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010449:Peptide Mapping; D020543:Proteome; D020539:Sequence Analysis, Protein; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D003435:Crotalid Venoms; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; D020543:Proteome; D045726:Metalloproteases; D008666:Metalloendopeptidases; C472493:bothropasin, Bothrops jararaca; D002122:Calcium Chloride