The influence of shaking upon trypsin and rennin and a comparison of this influence with that upon pepsin

At the December meeting of this Society we mentioned our studies of the effects of shaking upon ferments and reported that pepsin can be practically destroyed by shaking. Our studies were extended to other digestive ferments and we wish now to report very briefly that shaking proves to be very injurious also to trypsin and to rennin. Trypsin was tested by the casein method of Gross and the rennin was determined by the method of Blum and Fuld with slight modifications which will not be discussed here. Both ferments were shaken at room temperature, and at 33°C; also the influence upon the results of different rates of shaking and of changes in other conditions were investigated. We shall, however, state here only that the destructive effect of shaking upon trypsin and rennin is, as for pepsin, distinctly increased by increasing the rate of shaking and by increasing the temperature at which the shaking is carried on. There is a pronounced difference in the resistance to shaking between pepsin and trypsin under the conditions thus far studied, the latter being more readily affected. The destructibility of rennin runs practically parallel with that of pepsin.