139 



Retention of lectin properties by two HA-Con A conju- 

 gates, HA-Con A (PO ) and HA-Con A (NaCl) was examined by 

 adsorption to Sephadex G-75 (both eluted in volumes identi- 

 cal to native Con A following addition of . 1M D-glucose) , 

 hemagglutination (similar titers obtained with conjugates 

 from both reaction conditions and with native Con A) and 

 determination of the association constant for the chromogenic 

 ligand, PNPM. Although the K obtained for both HA-Con A 

 (PO ) and HA-Con A (NaCl) were slightly greater than native 

 Con A (Figure 20) , all of these results indicated that the 

 HA-Con A conjugates retained most if not all lectin associ- 

 ated activities. 



14 

 The stability of the ' C-HA-Con A conjugate bond to 



neutral hydroxy lamine treatment was examined for conjugates 



from both reaction conditions. Hydroxylamine under these 



conditions will hydrolyze any ester type linkages but will 



not affect peptide bonds (Carraway and Koshland, 1968) . 



The conjugates were 88% and 65% stable to hydroxylamine for 



the phosphate and NaCl reactions, respectively. Since Con 



A is devoid of any free sulfhydryl groups which could form 



side reactions with carbodiimide (Carraway and Koshland, 



1970) , these values represent the minimal amount of C-HA 



bound to Con A via peptide bonds. Table 5 summarizes the 



salient features of the HA-Con A conjugates in reference to 



native Con A. It can be concluded that these conjugates are 



essentially identical to native Con A with respect to their 



interaction with specific saccharide ligands. 



