Chinese Journal of Physiology

NON-PROTEIN SUBSTANCES FROM PROTEINS 79

We have studied also sheep’s serum globulin and hemoglobin by methods similar to that described above, excepting that tungstic acid was used for the removal of the protein. The former behaves like egg albumin (fig. 2), but the latter shows no detectable liberation of non-protein chromogenic substances. It would seem, therefore, that while the liberation of non-protein chromogenic substances may be a necessary result of denaturation of some proteins, it is not so for all proteins.

In our study on denaturation of egg albumin by dilute acids and alkalies, we observed that the course of liberation of the non-protein substances did not run parallel with that of denaturation and we concluded that the liberation of these non-protein substances was not an essential feature of the denaturation of proteins (6). In our paper on heat denaturation of egg albumin we mentioned the liberation of nonprotein chromogenic substances to show the similarility of denaturation of this protein by heat and that by acids and alkalies in the cold, and we did not take it as an observation upon which a general theory of denaturation could be based. Lloyd (1) attributes to us the view that the liberation of non-protein chromogenic substances is an evidence of the hydrolytic nature of denaturation. While we are of the opinion that denaturation is a mild hydrolysis or some other kind of degradation our view is not based on that observation.

LITERATURE 1. Lovo, D. J. Chemistry of the proteins, London, 1926, p. 243. 2. Mastin, H. anD REES, H. G. Biochem. J., 1926, 20, 759-762, 3. Wu, H. Chinese J. Physiol,, 1929, 3, 1-6. 4, Wu, H. anp Cuen, T. T. Chinese J. Physiol., 1929, 8, 7-28. 5. Wu, H. anp Wu, D. Y. J. Biol. Chem,, 1925, 64, 369-378, 6. Wu, H. anp YEN, D. J. Biochem. (Japan), 1924, 4, 345-384,