Abstract
(1) The authors carried out experiments on the effect of Mn and Co ions in a 1 mM concentration upon the splitting of glycyl-L-leucine by the dialyzed intestinal peptidase of pigs and remarkable variations, whether negative or positive, were found according to the methods of preparation of enzyme extracts.
(2) Negative effects (inhibitions) were obtained in the cases of using either a glycerine excract subjected to dialysis or a water extract subjected to dialysis and precipitated by acetone.
(3) Positive effects (activations) were obtained in the cases of using either a water extract subjected to dialysis after precipitation by acetone or a water extract subjected to dialysis after fractional precipitations by acetone and (NH4)2SO4.
In cases (2) and (3), the dialysis was carried out at 1° in a refrigerator under reduced pressure using a collodion sack, following S. P. L. SÖRENSEN.
(4) A survey of these remarkable variations is given in Table 1.
(5) With regard to the explanation of the reason why these remarkable variations, whether negative or. positive, occur, the authors have reserved to express their opinions, since mechanism on the activation of the metals upon the splitting of the peptide has not yet been fully clarified.
(6) It should also be noted here that such remarkable variations of the effect are not to be found in the cases of splitting glycylglycine and DL-leucylglycine. (cf Table 3)
