400 



REPORT ON WORK CARRIED OUT UNDER RESEARCH GRANT FROM 

 THE ROYAL SOCIETY OF SOUTH AUSTRALIA ON THE AZINE AND 

 AZONIUM PRECIPITATES OF THE PROTEOLYTIC ENZYME TRYPSIN. 



By Hedley Ralph Marston. 



The chemical similarity and resemblance of the physical reactions of the 

 protein bodies has led to the postulation of the chemical homogeneity of the 

 protein group. The distinct specificity of the proteins from diiTerent sources, _ 

 as shown by their biochemical activities, is remarkable in so much as the exist-' 

 ence of a demonstrably distinct protein from each species of animal or plant must 

 play an important role in the establishment of the morphological difterences and 

 uniqueness of physiological reactions which become manifest in the course of 

 evolution of new species. The close resemblance, though non-identity, of the 

 proteins from closely related species lends support to this hypothesis. ^^^ In the 

 development of the organism, the building up of the protein from its amino 

 acid integrals depends upon the catalytic effect exerted by the proteolytic 

 enzymes. These possibly exert their synthetic activity in a water poor system 

 existing at the surface of inert colloids within the cell. 



The remarkable specificity of the hydrolytic activity which the proteolytic 

 enzymes from different sources exert towards the various artificially prepared 

 poly-peptids "^-^ suggests the inference that a similar specificity would be exerted 

 in their synthetic activity. In other words, the specificity of the protein is 

 established by the catalyst through whose agency it was synthetised, that is, by 

 the proteolytic enzyme. 



In the complex Metazoa, the specificity of the proteolytic enzymes from 

 different tissues may be demonstrated by means of their selective activity 

 towards synthetic substrates. ^^^ 



The agency which brings about the differentiation of the tissue brings 

 about a simultaneous change in the proteolytic enzymes in that tissue. These 

 facts point to the possibility that the modification of the enzyme is determined by 

 physico-chemical conditions existing in the chromosomes, and so is closely allied 

 to the primary factor of tissue differentiation. 



With the elucidation of the structural configuration of the proteolytic 

 enzyme and its physico-chemical relationship with its substrate, the biologist 

 will accomplish a very decided step towards clarifying his conceptions of living 

 matter. The failure of the chemist to purify and identify the enzymes is due 

 to the fact of their extreme sensitivity to changes in the physical environment. 



Some years ago, T. Brailsford Robertson pointed out the occurrence of a 

 precipitate when a solution containing the proteolytic enzyme trypsin was added 

 to a solution of saifranine.^"'^ This observation was confirmed by Holzberg*^*"' 

 who demonstrated the proteolytic activity of the precipitate so produced. The 

 work, of which this is an account, was undertaken to study the nature of the 

 groupings which were responsible for the production of this precipitate. 



(1) Nuttall, G. F. H., "Blood Immunity and Relationship," Camb. University Press, 1904. 

 (•^) Adberhalden, E., and Collaborators, Zeit. fur Physiol. Chem. Numerous papers 

 appearing in this journal between 1904 and 1914. 



(3) Abderhalden, E., Zeit. fur Physiol. Chem. 



(4) Robertson, T. Brailsford, Jour. Biol. Chem., vol. 2, iv., p. 342. 

 Co) Holzberg, H., Jour. Biol. Chem., vol. xiv., 1913, p. 335. 



