136 



C. B. ANFINSEN AND K. R. REDFIELD 



20 30 40 50 60 



EFFLUENT VOLUME IN mL 

 F.g. 1. 

 O — O — O OD280 IRC-50 1x30 cm column 



X--X--X OD570 (ninhydrin). Phosphate buffer 0.2 M pH 6.47 



I 1 Samples for enzyme assay. 



Fig. 7. Chromatographic pattern obtained during IRC 50 chromatography of sub- 

 tilisin digests of native ribonuclease (from Richards, 1955). 



of derivative with time. To further characterize this inactive derivative, we 

 have separated workable amounts by large-scale chromatography as shown in 

 the next figure (Fig. 10). The material isolated in this way still contains lysine 

 as the N-terminal amino acid, but no new N-terminal amino residues have been 

 found. The intrinsic viscosity of the inactive derivative, both before and after 

 oxidation, is identical with that of control values for the native enzyme before 

 and after oxidation. 



The sedimentation constant of the derivative (Fig. 11) is also identical with 



