[Determination of the association constant K0 and the number of combining sites n of the mitogenic lectin I and its structural relationship to the nonmitogenic lectin II from the sponge Axinella polypoides (Schmidt) (author's transl)].

The association constant K0 and the number of combining-sites n for the mitogenic lectin I from the sponge Axinella polypoides was determined. K0 was found to be 2,8 . 10(2) 1/mol and n = 1. Immunoelectrophoretic investigations demonstrated, that lectin I and the nonmitogenic lectin II of Axinella polypoides have structural relationships but have also domains which are unique to them. The correlation between these findings, their carbohydrate specificity and mitogenicity is discussed.