THE SEDIMENTATION BEHAVIOR AND MOLECULAR WEIGHT OF PANCREATIC CARBOXYPEPTIDASE

Abstract

SUMMARY Crystalline bovine pancreatic carboxypeptidase sediments as a homo- geneous substance in the ultracentrifuge. The average value for the sedimentation constant, S~Q,, is 3.07 f 0.15 X lO+s. From this and diffusion data, the molecular weight is 33,800. The crystalline enzyme frequently contains a contaminating globulin with ~!&p,~ = 9.0 X 10-13. This inactive substance is insoluble at low ionic strengths near neutrality and can be separated from carboxypeptidase. BIBLIOGRAPHY 1. Aigren, G., and Hammarsten, E., J. Physiol., 90, 330 (1937). 2. Putnam, F. W., and Neurath, H., J. Biol. Chem., 166, 603 (1946). 3. AIISO~, M. L., J. Gen. Physiol., 20, 663 (1937). 4. Neurath, H., Elkins, E., and Kaufman, S., J. Biol. Chem., 170, 221 (1947). 5. Smith, E. L., Brown, D. M., Fishman, J. B., and Wilhelmi, A. E., J. Biol. Chem., 177, 305 (1949). 6. Svedberg, T., and Pedersen, K. O., The ultracentrifuge, Oxford (1940). 7. Stahmann, M. A., Fruton, J. S., and Bergmann, M.,