Activity of Phospho-nuclease. 



109 



3. Much evidence was collected that an absolute and relative 

 change of axes takes place in many instances and in two directions, 

 towards a symmetrical arrangement of the two members and, away 

 from such symmetry, and the extent of such changes was deter- 

 mined and measured. There is no clear evidence of any change in 

 polarity. 



66 (998) 



The influence of certain agents on the activity of phospho-nuclease. 



By Olaf Bergeim. 



[From the Laboratory of Physiological Chemistry of Jefferson Medical 



College.] 



The influence of certain chemical agents on the action of the 

 phospho-nuclease of the intestinal mucosa of the hog was studied. 

 In most cases 2 per cent, solutions of the substances tested were 

 used with 10 c.c. of a 20 per cent, tissue extract, and 5 c.c. of 2 per 

 cent, solution of neutral sodium nucleate. 



Salts of Ca, Ba, Sr, and Li inhibited the action considerably 

 while Mg, the phosphate of which is more soluble, did not inhibit. 

 Uranium salts entirely inhibited. The inhibition in these cases 

 appears to be due mainly to the removal of phosphate. The salts 

 of the heavy metals, Hg, Ag, Cu, and U almost entirely inhibited 

 while lead salts had less effect. The effect of these latter may be 

 largely due to destruction of the enzyme. 



Oxalate, tartrate, and fluoride had marked inhibitory effect 

 while citrate did not show this. With the exception of citrate 

 these form insoluble salts with Ca. Apparently the inhibitory 

 action is due to removal of Ca ions. The suggestion that a slightly 

 acid solution was favorable could not be confirmed. HC1 to make 

 0.05 per cent, solution practically stopped the action while an 

 equal amount of NaOH doubled the amount of phosphoric acid 

 set free. The same favorable effect was found when a little 

 NaHC0 3 was added and the mixture saturated with CO>. Ap- 

 parently a slightly alkaline or balancing solution is favorable. 

 NaCl, K 2 S0 4 and KI stimulated slightly. NH 4 N0 3 and potassium 

 arsenite inhibit somewhat. KCN in .25 per cent, neutral solution 



