88 ENZYMES 



During autolysis the changes are by no means limited to the 

 proteids. Glycogen is split into glucose very early, and the 

 sugar undergoes further changes. Fats are also split by the 

 lipase, fatty acids being found in autolyzed organs. Reducing 

 substances appear, and, as before mentioned, numerous volatile 

 fatty acids are produced. The increase in fat described by some 

 authors is probably only apparent, and due rather to the libera- 

 tion of the fat from its combination with the proteids so that it 

 is free and not " masked," as in normal organs. Lecithin is 

 also decomposed, yielding cholin. 



The nudeo-proteids seem to be attacked by the autolytic en- 

 zymes, as the purin bases are prominent among the products of 

 autolysis, and in quite different proportions from those obtain- 

 ing in digestion of the same tissues by other means. Apparently 

 autolytic enzymes, like trypsin, attack the proteid group of the 

 nucleoproteids, liberating the nucleic acids. These in turn are 

 attacked by specific enzymes, nucleases^ which liberate the purin 

 bases, which are further decomposed by specific enzymes, 

 guanase, adenase, etc. 2 



It is improbable that the intracellular enzymes are merely 

 pancreatic enzymes taken out of the blood by the cells, because 

 of the differences previously cited ; furthermore, Matthes 3 found 

 that the liver retained its autolytic power after the pancreas 

 had been extirpated (in dogs), and that the autolytic degenera- 

 tion of cut peripheral nerves went on just the same, indicating 

 that the autolytic enzymes do not owe their origin to the pan- 

 creas. 



RELATION OF AUTOLYSIS TO METABOLISM 



It having been shown that proteases are present in all cells, 

 the next question to be considered is, do they act only to destroy 

 tissues after death, or are they of importance in metabolism ? 

 Since it is presumably necessary for proteids to be split into 

 diffusible and easily oxidized forms in order that they may enter 

 the cell, and be built up into the cell proteids, or be decomposed 

 with the liberation of energy, the autolytic proteases may be 

 assumed to be of prime importance in proteid metabolism ; but 

 to prove it is another matter. Jacoby found that if he ligated 

 off a portion of the liver and let it remain in situ in the animal 

 the necrotic tissues showed an accumulation of leucin, tyrosin, 



1 Sachs, Zeit. physiol. Chem., 1905 (46), 337; Jones, Ibid., 1903 (41), 101, 

 and 1906 (48), 110. 



2 See Schittenhelra, Ibid. (42), 251 ; (43), 228; (46), 354. 



3 Arch. f. exp. Path. u. Pharm., 1904 (51), 442. 



