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Chain Structure of Cobra Venom Factor from Naja naja and Naja haje venom
Author(s) -
ZABERN I.,
PRZYKLENK H.,
VOGT W.
Publication year - 1982
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1982.tb00659.x
Subject(s) - venom , naja , chemistry , isoelectric focusing , trypsin , dithiothreitol , isoelectric point , microbiology and biotechnology , biochemistry , biology , enzyme
The chain structure of cobra venom factor, whether isolated from Naja naja venom (CVF n ) or from Naja haje venom (CVF h ), is similar. Both homologous proteins are composed of three disulphide‐linked chains (A, B, and C) with apparent molecular weights of 72,000, 54,000, and 27,000–35,000 for CVF n and 68,000, 51,000, and 30,000–32,000 for CVF h . That all three polypeptides are integral parts of CVF was demonstrated by investigation of the chain pattern after partial reduction. Reduction with 1–2 mM dithiothreitol under nondenaturing conditions yielded free B‐chain, together with an intermediate product composed of disulphide‐linked A‐ and C‐chains. The C‐chain was heterogenous when investigated by electrophoresis in polyacrylamide slab gels in the presence of SDS. Similarly, isoelectric focusing of CVF n and CVF h showed a multiplicity of bands in the pH range 5.2–6.4. Limited tryptic digestion resulted primarily in the fragmentation of the B‐chain. CVF h is much more sensitive to tryptic attack than CVF n . In all our preparations of CVF h a partial, trypsin‐like fragmentation of the B‐chain was detectable to various extents.