alpha-chymotrypsin and 2-iodosobenzoic-acid

The amino acids of the chymotrypsin inhibitor (ECI) from the Erythrina variegata seeds have been sequenced. The sequence was solved by analysis of peptides derived from the protein by enzymatic digestions with trypsin and Staphylococcus aureus V8 proteinase, as well as by chemical cleavage with o-iodosobenzoic acid. The ECI consists of 179 amino acid residues with a pyroglutamic acid as the N-terminal residue and has a calculated molecular weight of 19,791. Comparison of this sequence with the sequences of the two trypsin inhibitors, ETIa and ETIb, from the E. variegata seeds shows that about 60% of the residues of ECI are identical to those of ETIa and ETIb and that the reactive sites, Arg63, in ETIa and ETIb change to Leu64 in ECI.

Topics: Amino Acid Sequence; Chromatography, High Pressure Liquid; Chymotrypsin; Iodobenzoates; Molecular Sequence Data; Molecular Weight; Plant Proteins; Seeds; Serine Endopeptidases; Sulfhydryl Reagents; Trypsin

The complete amino acid sequence of a thrombin-like enzyme with gyroxin activity isolated from the venom of the bushmaster snake Lachesis muta muta was determined by automated and DABITC/PITC microsequencing of the intact protein; fragments derived from it by separate cleavages with cyanogen bromide, iodosobenzoic acid and hydroxylamine; and peptides resulting from enzymatic digestions with trypsin, pepsin, chymotrypsin, and elastase. The protein, which is composed of 228 residues, contains four putative sites of N-linked glycosylation and exhibits significant sequence similarities with other serine proteases reported from snake venoms.

Topics: Amino Acid Sequence; Binding Sites; Chymotrypsin; Crotalid Venoms; Cyanogen Bromide; Glycosylation; Hydroxylamine; Hydroxylamines; Iodobenzoates; Molecular Sequence Data; Pancreatic Elastase; Pepsin A; Peptide Fragments; Sequence Analysis; Sequence Homology, Amino Acid; Serine Endopeptidases; Thrombin; Trypsin

The amino acid sequence of the neutral zinc protease from Bacillus mesentericus strain 76 (MCP 76) has been determined by using peptides derived from digests with trypsin, chymotrypsin, and cyanogen bromide and from cleavage with o-iodosobenzoic acid. The peptides were purified by means of gel filtration and reversed-phase high-performance liquid chromatography and analyzed by automatic sequencing. The protein contains 300 amino acid residues. It proved to be identical with the neutral protease deduced from the DNA precursor sequence of Bacillus subtilis. The residues for zinc and substrate binding are conserved, whereas the number of calcium binding sites is reduced compared to thermolysin. A classification of the neutral zinc protease is discussed.

Topics: Amino Acid Sequence; Bacillus; Carboxypeptidases; Carboxypeptidases A; Chromatography, Gel; Chromatography, High Pressure Liquid; Chymotrypsin; Iodobenzoates; Metalloendopeptidases; Molecular Sequence Data; Peptide Fragments; Trypsin

The complete primary structure of the fimbrial protein of the K88 antigen has been elucidated. This protein, which makes up the building block for the macromolecular structure that comprises a fimbria, consists of 264 amino acid residues in a single polypeptide chain. The K88 antigen was fragmented by chemical cleavage with cyanogen bromide, and by subsequent enzymatic sub-cleavage of resulting fragments with trypsin and chymotrypsin, and was additionally cleaved with o-iodosobenzoic acid. Peptides were sequenced by manual Edman degradation. The carboxy-terminal part of the molecular is remarkable in being almost devoid of charged amino acid residues and is highly hydrophobic. Furthermore, this part of the structure could have a specific function as molecular anchor.

Topics: Amino Acid Sequence; Antigens, Bacterial; Antigens, Surface; Chymotrypsin; Cyanogen Bromide; Escherichia coli; Escherichia coli Proteins; Fimbriae Proteins; Iodobenzoates; Peptide Fragments; Trypsin