THE INACTIVATION OF FERTILIZIN AND ITS CONVERSION TO THE "UNIVALENT" FORM BY X-RAYS AND ULTRAVIOLET LIGHT

¹ From the William G. Kerckhoff Laboratories of the Biological Sciences, California Institute of Technology, Pasadena, and the Marine Biological Laboratory, Woods Hole

1. The X-ray inactivation of Arbacia punctulata fertilizin reported by Richards and Woodward (1915) and by Evans, Beams and Smith (1941) is confirmed. Further data on this inactivation are presented in terms of Roentgen units, fertilizin concentration and sperm concentration.

2. It is shown that ultraviolet light is effective in the inactivation of Strongylocentrotus purpuratus and Lytechinus anamesis fertilizin.

3. Arbacia fertilizin which had been almost completely inactivated by X-rays, as judged by its ability to agglutinate sperm, lost none of its power to react with sperm. Thus, sperm treated with this fertilizin showed the same resistance to subsequent agglutination by untreated fertilizin as did sperm which had reversed after treatment with unirradiated (control) fertilizin.

4. Strongylocentrotus and Lytechinus fertilizins whose sperm agglutinating powers had been completely destroyed by ultraviolet light likewise retained their original sperm combining powers, as indicated by their ability to render sperm non-reactive to untreated fertilizin.

5. Tyler's (1941) view that fertilizin may be converted to a non-agglutinating, "univalent" form by splitting the fertilizin molecule into fragments, each having but one reacting group, is considered the most reasonable explanation for the results.