158 



THE BIOLOGY OF HYDRA : 1961 



rr 



J 



Fig. 1. Ultracentrifuge pattern of purified inhibitor at 59,000 r.p.m. (6). 



ments indicate the molecular weight to be less than 50,000. 

 Chemical tests show the presence of protein. The ultraviolet 

 absorption spectrum (Fig. 2) is qualitatively very similar to that 

 produced by proteins such as serum globulins. There are no 

 peaks in the visible spectrum. All of our characterization studies 

 affirm the presence of a protein in the purified inhibitor and, as 



0.8 ~r 



240 250 260 270 280 290 300 310 320 330 360 



WAVE LENGTH (tu^) 



Fig. 2. The ultraviolet absorption spectrum of the purified inhibitor in 

 phosphate buffer (6). 



