Isolation and properties of a soluble fraction of Paracentrotus lividus sea urchin eggs responsible for the calcium-induced oxidative burst.

The system responsible for the oxidative burst (OB) activity in Paracentrotus lividus eggs is different from those described earlier for other sea urchin species. The OB in P. lividus is associated with a soluble fraction resulting from centrifugation at 150,000 g. A low-molecular-weight, -SH-containing molecule present in this supernatant is required for the OB activity. The sulfhydryl reagent N-ethylmaleimide completely inhibits the calcium stimulated OB activity of intact eggs in the presence of the calcium ionophore A23187, suggesting that this requirement of low-molecular-weight -SH-containing molecules for OB exists also in vivo.