Purification and characterization of Streptomyces sialidases

Some strains of Streptomyces produce sialidases. Two sialidases were purified over 1,000-fold from a culture filtrate of two Streptomyces species. They had the same properties in molecular weight, behavior to ions and other reagents, and substrate specificity. They showed very small differences in kinetic properties, pH optima, and heat stability. These Streptomyces sialidases differed markedly from Clostridium perfringens sialidase in molecular weight, p-chloromercuribenzoate sensitivity, and substrate specificity. Approximate molecular weights of the sialidases from Streptomyces and C. perfringens were 32,000 and 57,000, respectively. p-Chloromercuribenzoate (10(-3) M) caused complete inhibition of C. perfringens sialidase but not of Streptomyces sialidases.