106 



castor bean type II (CB-II) , WGA and lentil lectin were only 

 slightly decreased. Soybean agglutin (SBA) and phytohemag- 

 glutin (PHA) demonstrated significant reduction in hemagglu- 

 tination titer after conjugation. With the exception of 

 SBA and PHA, all of the ADGG-lectin conjugates retained 

 essentially equivalent agglutinating activity to that of 

 the native lectin. 



Retention of the amanitin associated ability to inter- 

 act with RNA polymerase II was examined for ADGG-Con A 

 conjugates. The determination of the inhibition constant 

 for calf thymus RNA polymerase II is shown in Figure 22. 



This preparation, containing 3.6 moles ADGG per mole of 



-9 

 Con A, had an inhibition constant K , of 25 x 10 M. Under 



the conditions used to establish this value, native Con A 

 at equivalent concentrations to that present with the con- 

 jugate did not cause inhibition of polymerase activity. 

 The inhibition by ADGG-Con A was unaffected by the presence 

 of . 1M D-glucose further establishing the specificity of 

 the inhibition as being derived for the amanitin portion of 

 the conjugate. 

 Interaction with Cells 



The binding of ADGG-Con A conjugates to cell surface 



glycoproteins present on cultured cells was investigated by 



125 

 competition experiments with I-labeled Con A. The amount 



125 

 of I-Con A bound by CHO cells was first determined for 



a 15 minute exposure at 22°C. The results of this binding 



for CHO H-7 cells and H-7 Wcr cells, a line derived from 



