2000 Volume 41 Issue 4 Pages 257-262
Extracellular keratinase (Ekase) 48-, 34- and 31.5-kDa polypeptides, which were isolated from Microsporum canis and examined by immunoblotting reacted with a monoclonal antibody against Ekase of M. canis.
We analyzed the amino acid and determined the first 17 amino acid NH2-terminal sequences of the 48-, 34- and 31.5-kDa polypeptides. These polypeptides had a high aspartic acid, glycine and alanine content, respectively. The first 17 amino acid residues of the 34-kDa polypeptide were homologous to those of thermomycolin. This indicated that the 34-kDa polypeptide of Ekase is homologous to the thermomycolin produced by Malbrachea pulchella. Furthermore, Ekase was very heat-stable in the presence of 50mM CaCl2 at 55°C, since 50% of the initial activity remained. In contrast, no activity was detected after heating in the absence of CaCl2. These results indicate a close relationship between dermatophytes and M. pulchella.
