Aprotinin,a carbohydrate-binding protein

Summary Evidence is presented for a carbohydrate-binding property of aprotinin, which is preserved both in a fluorescein isothiocyanate (FITC) conjugate and a cyanogen bromidelinked Sepharose conjugate of the protein. Both conjugates similarly retain their tryptic and chymotryptic inhibitory properties. The FITC conjugate is shown to be a single species with respect to charge and to molecular weight and shows a specific binding of normal materials containing sialosyl or uronosyl groups, which accords with its histochemical behaviour. The Sepharose-conjugate showed a similar specificity.R.W.S. holds a grant from the Cancer Research Campaign. We thank Dr. G. M. W. Cook for discussion and advice.