Properties and partial purification of the sperm attractant of Tubularia

Abstract

The investigations leading to an explanation of the mechanism of sperm chemotaxis in the hydrozoa depend heavily on purification and identification of the compounds responsible for the attraction. The substance (s) are of low molecular weight, are stable to heat and to high and low pH under moderate conditions, and are highly positively charged. Recent work using the attractant from Tubularia indicates that ion-exchange chromatography coupled with the proper gradient elution techniques is beginning to yield partially purified attractant. The biological activity is eliminated after strong-acid hydrolysis and after treatment with crude proteolytic enzymes, like pronase and pancreatin. The active components of these mixtures of enzymes are neutral proteases with a serine residue in the active site. The stability of the molecule (s) to pH, their apparent ninhydrin-insensitivity, and their chromatographic behavior are indicative of a low molecular-weight peptide, possibly one of the cyclic peptides. Promising avenues leading to further purification have been opened up by the work reported here, and it would appear to be only a matter of time before pure attractant is available for chemical analysis. Copyright © 1974 by the American Society of Zoologists.