Chemical properties of heat-stable enterotoxins produced by enterotoxigenic Escherichia coli of different host origins

Abstract

Five heat-stable enterotoxins (STs) produced by enterotoxigenic Escherichia coli strains of porcine, bovine, and human host origins have been purified to apparent homogeneity. The STs with biological activity in suckling mice and piglets (STas) contained 18 amino acid residues, 10 amino acids with a high proportion of acidic amino acids, and 6 half-cystines. The carboxy-terminal and amino-terminal residues of all STaS were tyrosine and asparagine, respectively. All five STa preparations were homogeneous by several criteria: (i) a single symmetrical peak on gel filtration, (ii) a single fluorescent band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, (iii) single carboxyl-terminal and amino-terminal residues, and (iv) amino acid analysis data that indicated a stoichiometric relationship between the component amino acids. The isoelectric

Characterization of the cattle serum antibody responses against TEM β-lactamase and the nonimmunogenicEscherichia coliheat-stable enterotoxin (STal)

“…DNA hybridization tests have indicated that STa can be divided into STaI and STaII. STaI and STaII have been purified and sequenced from human, bovine and porcine isolates (Chan & Giannella, 1981;Lallier et al, 1982;Dreyfus et al, 1983). The STaI and STaII sequences consist of 18 and 19 amino acids, respectively (Moseley et al, 1983).…”

Purification of the STB enterotoxin of Escherichia coli and the role of selected amino acids on its secretion, stability and toxicity

“…STA and STB are totally distinct toxins with unique biological and biochemical properties (Burgess et al, 1978;So and McCarthy, 1980). The alleles of ST^s (estA) encode either 18-or 19amino-acid extracellular peptides (Martinez-Cadena et al, 1981;Dreyfus et al. 1983) which result from two discrete proteolytic cleavages of a 72-amino-acid precursor (Rasheed et al.…”

Characterization of heat-stable enterotoxin from a hypertoxigenic Escherichia coli strain that is pathogenic for cattle

“…Tyrosine was the carboxy-terminal residue of the STa peptide, as determined by carboxypeptidase Y digestion. The biochemically characterized STa's of WSUH, and L1 strains were identical to STa's characterized from bovine ETEC B41, B44, M420, and M524 (2,20).…”