title: Naja melanoleuca cobra venom contains two forms of complement-depleting factor (CVF).
abstract: Two forms of complement-depleting cobra venom factor (CVFm1 and CVFm2), possessing molecular masses of 142.6 kDa (CVFm1) and 143.1 kDa (CVFm2), according to MALDI mass-spectrometry, were isolated from the Naja melanoleuca cobra venom. As shown by polyacrylamide gel electrophoresis in the presence of SDS, both forms similarly to factor from the Naja kaouthia cobra venom (CVFk) consist of three polypeptide chains with molecular masses of about 70, 50, and 30 kDa, the two large subunits being glycosylated. As determined by MALDI mass-spectrometry, 30 kDa subunits of CVFm1 and CVFm2 have considerably different finger-prints of tryptic digests that suggests differences in their amino acid sequences. A study of activity in vivo has shown no significant differences in C3 consumption by CVFm1, CVFm2 and CVFk in mouse blood. However, as shown by an immunoassay method, they differ in their ability to activate the complement system via C3 conversion, the ratio of these activities for CVFm1:CVFm2:CVFk being 2.5:1.6:1. Kinetic studies using a hemolytic test showed that complement depletion by CVFm1 is faster than that by CVFm2. Thus, for the first time the presence in a single venom of two forms of CVF differing by both amino acid sequence and biological activity has been shown.
authors.affiliation: Laboratory of Neuropeptide Receptors, Shemyakin & Ovchinnikov Institute of Bioorganic Chemistry RAS, ul. Miklukho-Maklaya 16/10, Moscow V-437, 117997 GSP, Russian Federation.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Osipov
authors.forename: Dmitry Yu
authors.initials: DY
authors.lastname: Mordvintsev
authors.forename: Vladislav G
authors.initials: VG
authors.lastname: Starkov
authors.forename: Lyudviga V
authors.initials: LV
authors.lastname: Galebskaya
authors.forename: Elena V
authors.initials: EV
authors.lastname: Ryumina
authors.forename: Peter P
authors.initials: PP
authors.lastname: Bel'tyukov
authors.forename: Leonid V
authors.initials: LV
authors.lastname: Kozlov
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Romanov
authors.forename: Yvon
authors.initials: Y
authors.lastname: Doljansky
authors.forename: Victor I
authors.initials: VI
authors.lastname: Tsetlin
authors.forename: Yuri N
authors.initials: YN
authors.lastname: Utkin
mesh_terms: D000818:Animals; D003176:Complement C3 / Q000378:metabolism*; D015941:Complement Hemolytic Activity Assay; D004546:Elapid Venoms / Q000302:isolation & purification* / Q000378:metabolism*; D017815:Elapidae; D004591:Electrophoresis, Polyacrylamide Gel; D007118:Immunoassay; D007700:Kinetics; D013058:Mass Spectrometry; D051379:Mice
chemical_list: D003176:Complement C3; D004546:Elapid Venoms