Partial amino acid sequence of the basic crotalus phospholipase A

Monoclonal antibodies to Mojave toxin and use for isolation of cross-reacting proteins in Crotalus venoms

Hybridomas secreting monoclonal antibodies against Mojave toxin were established. The antibodies were used for identifying cross-reacting proteins in individual C. s. scutulatus and other Crotalus venoms and to isolate Mojave toxin. The antibodies recognized five bands with a pI range from 5.1 to 6.1 in immunoblots of electrofocused crude venom and Mojave toxin purified by immunoaffinity chromatography. The specificity of the antibodies was for the basic subunit of the toxin, which resolved into four bands of pI between 9.3 and 9.6. Individual C. s. scutulatus venoms of snakes from Texas and southern Arizona had multiple bands with pI's ranging from 4.9 to 6.3. Cross-reacting proteins were also recognized by the antibodies in the electrophoresed venoms of C. basiliscus, C. d. durissus, C. d. terrificus, C. h. horridus and C. v. concolor, and may be isolated by immunoaffinity chromatography with the monoclonal antibodies.

Naja mossambica mossambica venom. Purification, some properties and the amino acid sequences of three phospholipases A (CM-I, CM-II and CM-III)

Three phospholipases A, CM-I, CM-II and CM-III, were purified from Naja mossambica mossambica venom by gel filtration on Sephadex G-50 followed by ion-exchange chromatography on CM-cellulose. They comprise each 118 amino acid residues and are close-linked by seven intrachain disulphide bridges. The complete primary structure of the three phospholipases A have been elucidated. The sequences and the invariant amino acid residues of CM-I, CM-II and CM-III resemble those of phospholipases A from other snake venoms and also from porcine pancreas. However, the letality (LD50 values) of the three phospholipases A from Naja mossambica mossambica venom, differ among themselves, and are also much higher than the LD100 value encountered for notexin from Notechis scutatus scutatus venom.

Isolation and characterization of three phospholipases A from the crotoxin complex

1. Three phospholipases A (phosphatide acyl-hydrolase, EC 3.1.1.4) have been isolated from the crotoxin complex, the main toxic compound of the Crotalus durissus terrificus venom. 2. Two basic phospholipases A were highly purified from the crotoxin complex by single chromatography on carboxymethyl cellulose. The yields were 10% and 38% (w/w), respectively. They showed no differences with regard to isoelectric point, enzymatic activity, immunological properties, and toxicity. One acidic phospholipase A, purified to a final yield of 1-3% by chromatography on carboxymethyl cellulose, gel filtration on Sephadex G-50, and chromatography on DEAE-cellulose, was found to have one third of the specific enzymatic activity of the basic enzymes. The acidic phospholipase A was nontoxic and antigenically different from the basic enzymes. 3. Crotapotin, an acidic peptide of the crotoxin complex (31% yield, w/w), potentiated the toxicity and inhibited the enzymatic activity of the basic phospholipase A isoenzymes, but did not interact with the acidic phospholipase A. 4. The purified enzymes were homogeneous with respect to cellogel electrophoresis, polyacrylamide gel electrophoresis, dodecyl sulfate-gel electrophoresis, immunoelectrophoresis, and isoelectric focusing. 5. The molecular weights of the three phospholipases were found to be in the same range as determined by gel filtration in 6 M guanidine - HCl (14 500) and dodecyl sulfate-gel electrophoresis (15 800). The isoelectric points of these enzymes were at 9.7 and 4.8 for the first two and the third, respectivlar. The acidic enzyme contained more acidic instead of basic amino acid residues. The two methionine residues of each phospholipase were found to be positioned nearby the NH2 - and the C-terminal of the protein chains. A third methionine residue was demonstrated in the acidic phospholipase A. Fingerprint maps of the basic enzymes showed only slight differences. 7. NH2 - and C-terminal sequence analyses indicated a striking homology between the three Crotalus phospholipase A isoenzymes and several phospholipases from other sources.