The Incorporation and Fate of [35S]-Sulfate in the Jelly Coat of Xenopus laevis Eggs

[35S]-sulfate injected into ovulating Xenopus laevis was incorporated into eggs and egg jelly coats. The extent of [35S] incorporation was dependent on the dose administered and time the eggs were ovulated after injection. The radioactivity was incorporated predominately into the innermost jelly coat layer J1; J1 contained the majority if not all of the sulfate in the jelly coat as determined by chemical analysis for sulfate. The [35S] incorporated was chemically in the form of sulfate esters as determined by chromatography of acid hydrolysates. Hydrolysis rates the [35S]-sulfate from the jelly coat macromolecules and the infrared absorption spectra of jelly suggested that sulfate was present as sugar ester of a secondary axial hydroxyl group, most likely on the C4 position of Ga1, Ga1NAc, or Fuc residues. The sulfated jelly coat macromolecules were not incorporated into the egg during its passage through the oviduct nor into the embryo during development up to the hatching stage.