CH. VIII.] AUTOLYSIS. 22Q 



The rate and degree of hydrolysis varies considerably 

 with the nutritive condition of the tissue at the moment 

 of death and on the reaction of the medium in which the 

 autolysis proceeds. In general it may be stated that it is 

 accelerated by the previous starvation of the animal and 

 by an acid reaction, the optimum being between P H = 5 

 and P H = 6. 



"The fact that autolysis is accelerated by starvation 

 suggests that it is the mechanism by means of which 

 the amino-acids liberated are deaminised to ammonia and 

 an acid. The latter is oxidised to CO 2 and water, either 

 directly or after passing through the stage of carbohydrate. 

 These products being removed by the lungs, the net result 

 is a supply of ammonia for the neutralisation of the acid 

 originally causing the disturbance. It is noteworthy that 

 the products of autolysis contain much more ammonia 

 than is found in the products of action of trypsin and 

 erepsin. 



273. The autolysis of ox kidney. Ox kidney is freed from 

 fat, finely minced in a machine and weighed. The pulp is treated 

 with 3 times its weight of 0*2 per cent, acetic acid and shaken with 

 toluol, as a preservative. The mixture is incubated for 3 or 4 days 

 at 38 C. It is then filtered from an insoluble residue of haematin, 

 nuclein, etc. The filtrate is treated with more toluol and incubated 

 for another 7 to 9 days. 



A. Boil about 10 cc. Note the heat coagulation of undigested 

 native protein. It may be necessary to adjust the reaction to get 

 complete coagulation. Filter off the coagulum and to a portion of 

 the filtrate add bromine water, drop by drop. A red or purple 

 colour indicates the presence of free tryptophane (see Ex. 261). 



B. Boil another portion of the mixture as before. Cool 10 cc. 

 of the filtrate, add 10 drops of strong sulphuric acid and cool again. 

 Add an equal volume of the mercuric sulphate reagent of Hopkins 

 and Cole (see p. 89), mix and allow to stand for 10 to 20 minutes. A 

 precipitate is obtained which consists of mercury compounds of 

 tryptophane and of the purine bases. Filter. 



