Studies on pancreatic proteinase I.

IN the extensive literature concering the nature and action of trypsin there appears to be no record of a systematic study of factors affecting the earliest stage of protein breakdown by this enzymic complex or by its isolated proteinase component. Waldschmidt-Leitz and his collaborator [1931; 1932; 1933] have shown that the trypsin complex can be separated into several components each of which effects, characteristically, the degradation of substances of more or less definite complexity or structure. Systematic examination of the kinetic be- haviour of each enzyme, acting on suitable substrates, should lead to a better understanding of the complex as a whole and should assist in clarifying certain problems concerning which the literature is sometimes inconclusive and con- tradictory. Estimations of the increasing amino-nitrogen resulting from the action of trypsin on a protein reveal, by themselves, nothing more than the additive effects of the enzymic components acting upon their respective sub- strates. Such experimental data have only a very limited value in elucidating the nature of the action of any single component.