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The Macrotyloma axillare plant, belonging to the Leguminosae family, is a perennial climbing or trailing herb 0.2–3.5 m long. The plant is indigenous to South Africa and it occurs in the warm dry northern parts of the Transvaal. It has been introduced into Australia, where the seed are used as animal food. Two protease inhibitors, DE-3 and DE4, were purified from Macrotyloma axillare seed by gel filtration on Sephadex G-50 followed by ion-exchange chromatography on DEAE- cellulose. They each comprise 76 amino acid residues including 14 half-cystine residues. The complete primary structures of the two protease inhibitors have been elucidated and their sequences are 67% identical. The inhibitor specificities, the sequences, the invariant amino acid residues and the reactive inhibitor sites of protease inhibitors DE-3 and DE-4 resemble the corresponding properties of the Bowman­Birk double-headed protease inhibitor group. The cysteine residues are in similar locations to those in protease inhibitors of known structure so they are presumed to rink similarly. [ABSTRACT FROM AUTHOR]

Three toxins (CM-2, CM-11 and CM-12) were purified from Naja haje haje (Egyptian cobra) venom. Whereas toxin CM-11 contains 65 amino acid residues and five intrachain disulphide bridges, toxin CM-2 and CM-12 comprise, respectively, 61 and 62 residues but both contain four disulphide bridges. The complete primary structures of the three toxins have been established. The sequence and the invariant amino acid residues of CM-2 resemble those of part of a long neurotoxin, a short neurotoxin and a cytotoxin. The sequence of CM-11 reveals that it is a homologue of the neurotoxins and to some extent also a cytotoxin. The immunochemical properties and the sequence of CM-12 suggest that it is related to the cytotoxin group. Further, the sequences of CM-11 and CM-12 from Naja haje haje venom show a high degree of homotogy with those of the corresponding toxins isolated from Naja haje annulifera or Naja melanoleuca venoms. [ABSTRACT FROM AUTHOR]

Two isoenzymes of phospholipase A (fraction DE-I and DE-JI) were isolated from the venom of Hemachatus haemachatus (Riughals) by gel filtration on Sephadex 0-50 and by ion-exchange chromatography on DEAE-cellulose. Fraction DE-I was homogeneous by various physicochemical criteria. The enzyme comprises 119 amino acid residues and is cross-linked by seven disulphide bridges. The values of the molecular weight of fraction DE-I from gel filtration in the presence of calcium ions, also by the dodecylsulphate gel method and calculated from the amino acid composition were close to 13500. The complete amino acid sequence of phospholipase A (fraction DE-I) was elucidated. The reduced and S-carboxymethylated enzyme was digested with trypsin, chymotrypsin, thermolysin and subtilisin and the peptides purified by DEAE-cellulose chromatography, gel filtration and chromatography or electrophoresis on paper. The amino acid sequences of the intact enzyme and the pure peptides were determined by the Edman procedure, either through the use of the automatic sequencer or by manual manipulation. The chymotryptic digest provided the necessary overlapping peptides for aligning the tryptic peptides. The amino acid sequence of Hemachatus haemachatus phos- pholipase A (fraction DE-I) shows a high degree of homology with the three isoenzymes of phospho- lipase A from Naja melanoleuca and is also homologous with the phospholipase A from Bitis gabonica and porcine pancreas. [ABSTRACT FROM AUTHOR]