224 THE HYDROLYZING ENZYMES 



any appreciable synthesis of Triolein from oleic acid and glycerol in the 

 presence of fifty per cent, of water, although when we start with 

 triolein in this proportion of water an appreciable amount of triolein 

 remains unhydrolyzed at the end of prolonged hydrolysis. The 

 presence of the enzyme in this case appears to selectively accelerate 

 hydrolysis, and if this is the case then the enzyme must be consumed in 

 the process. 



Among the proteins the synthesis of a protamine, Salmine, from a 

 concentrated solution of its digestion-products has been accomplished 

 by A. E. Taylor, who employed an unusually stable Trypsin obtained 

 by extracting the liver of a mollusc (Schizothoerus nuttalli) with glycerol, 

 and adding this in very large amounts to a saturated solution of the 

 amino-acids which finally result from the hydrolysis of protamine. 

 Only a small proportion, about one-half of a per cent., of the original 

 protein was recovered and that only after a lapse of five months. The 

 identity of the synthetic protein with salmine was deduced from 

 analysis and general physical behavior. 



When Sodium Caseinate in neutral solution is subjected to hydrolysis 

 by Pepsin a group of infraproteins results, which are collectively termed 

 Paranucleins, and which subsequently undergo further hydrolysis, 

 with the production of proteoses and peptones. The paranucleins 

 resemble casein in being soluble in dilute alkalies and precipitable by 

 acetic acid, but are less soluble in dilute mineral acids than casein 

 itself. When to the concentrated solution obtained by evaporating 

 down the final products of the prolonged peptic hydrolysis of casein, 

 a very large proportion of fresh pepsin is added, after a comparatively 

 brief period (forty-eight hours) at 40 C. a precipitate is formed in 

 the mixture which appears to be identical with paranuclein. In this 

 case the identity has been confirmed by immunological methods. The 

 antiserum to casein or paranuclein produced by repeatedly injecting 

 these substances into the circulation of rabbits yields no precipitate 

 either with the products of the complete peptic hydrolysis of casein or 

 with pepsin, but it does yield a precipitate with the synthetic para- 

 nuclein obtained in the manner outlined, and this precipitate binds 

 the antibodies to casein and paranuclein which the serum contained. 

 Since the Antibodies which appear in the circulation of animals as a 

 result of immunizing them against proteins are in the highest degree 

 specific, yielding precipitates only with the protein employed in the 

 immunization or with inf raprotein derived from it by partial hydrolysis 

 the synthetic product may be considered to be thus clearly identified 

 with the infraproteins which are the first cleavage-products of casein. 



In this case, however, rather definite indications were obtained that 

 the Synthesizing Enzyme is not identical with pepsin itself, for it proved 

 possible to bring about the synthesis a great deal more rapidly at 70 C. 

 than at 40 C., while the hydrolyzing activity of pepsin is inhibited 

 altogether at this temperature. Moreover not every preparation of 

 pepsin will yield the synthesis. It has been suggested that the active 



