Louis Chaiet

The properties of streptavidin, a biotin-binding protein produced by Streptomycetes

Abstract Streptavidin, a crystalline protein isolated from fermentation filtrates of streptomycetes has been reported to have biotin-binding ability similar to avidin. A comparison has been made between streptavidin and avidin from egg white using microbiological, physical, and chemical methods. Streptavidin binds four molecules of biotin. Chemical analysis shows the absence of hexoses and amino sugars associated with avidin and reveals differences in amino acid content. Electrophoretic studies give different mobilities for streptavidin and avidin. Thus, streptavidin is a new type of biotin-binding protein.

Avermectins, New Family of Potent Anthelmintic Agents: Isolation and Chromatographic Properties

The avermectins, a family of new anthelmintic agents, were isolated from the mycelia of Streptomyces avermitilis. Four closely related major components and four homologous minor components were separated from the complex. Solvent extraction, solvent partition, and adsorption methods were used to isolate and purify the complex; novel partition chromatography systems using Sephadex LH-20 were used to separate the components. A reverse-phase high-pressure liquid chromatography assay for the quantitative determination of all components was used extensively to monitor the purification methods.