SEPTEMBER, 1937
INDUSTKIAL AND ENGINEERING CHEMISTRY
apparently 760 times more germicidal than 5 per cent phenol, as judged on the basis of phenol coefficient figures of the two germicides, it is not actually 760 times better as an antiseptic under practical conditions. The phenol coefficient of antiseptics, therefore, cannot be interpreted in terms of practical value. Other examples could be given of the impracticability of the phenol coefficient as applied to antiseptics. There is no justification on scientific, technical, or practical grounds for the use of this figure as a means of indicating the germicidal efficiency and practical value of this class of preparations. The phenol coefficient figure cannot possibly be used as an index of the value of such preparations for general use or even for special applications. Also, since antiseptics are marketed ready for use or the dilutions specified on the label, the phenol coefficient need not and really cannot be used for determining the proper dilution for use in practice. Many antiseptics act in a manner so different from phenol that any comparison to the germ-killing power of carbolic acid is out of the question. Antiseptics should therefore be tested directly on the bacteria which will be met in practice by the special F. D. A. tests for antiseptics designed specially for the purpose.
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Literature Cited Brewer, C. M., and Reddish, G. F., J. Bad., 17,44 (1929). Carswell, T. A., and Doubly, J. A., ISD.ENG.CHEM.,28, 1276 (1936). Klarmann, E., and Shternov, V. A.,Ibid., 28,369 (1936). Lange, N. A,, Handbook of Chemistry, p. 1185, Sandusky, Ohio, Handbook Publishers, Inc., 1934. P u b . Health Repts. (Reprint 675), 36, 1559 (1921). Reddish, G. F., Am. J . P u b . Health, 15, 534 (1925). Ibid., 16, 283 (1926). Ibid., 17, 320 (1927). Reddish, G. F., S.Am. P h a r m . Assoc., 25, 1117 (1936). Ibid., 18, 237 (1929). Reddish, G. F., J . L a b . Clin. l e d . , 14, 649 (1929). Reddish, G. F., in Jordan and Falk’s “Newer Knowledge of Bacteriology and Immunology,” Univ. Chicago Press, 1928 Reddish, G. F., Soap, 11, 95 (1935). Reddish, G. F., and Drake, W. E., S.Am. Med. Assoc., 91,712 (1928). Rideal, S., and Walker, J. T. A,, “Approved Technique of the Rideal-Walker Test,” London, H. K. Lewis & Co., 1921. Simmons, J. S.,J. Am. Med. Assoc., 91,704 (1928). Tinker, M. B., and Sutton, H. B., Ibid., 87,1347 (1926). U. S.Dept. Agr., Circ. 198 (1931). Varley, J. C., and Reddish, G. F., J . Bact., 32,215 (1936). RBCEIVED September 10, 1937. Presented before Section X, Subsection on Pharmacy a t t h e meeting of t h e American Association for t h e Advancement of Science, December 30, 1935.
PAPAIN Effect of Storage upon Activity ROBERT R. THOMPSON University of Hawaii, Honolulu, Hawaii
I
N VIEW of the fact that papain is inactivated by oxidation, it is of practical importance to ascertain t o what extent air affects the stability of the dried papaya latex. A number of samples of papain were prepared from fresh latex several years ago and furnish an opportunity to observe the changes that occur upon storage. The proteolytic activity of papain preparations is dependent upon the presence of a sulfhydryl group. Most samples of papain require reduction before they reach maximum activity. By the use of a reducing agent such as hydrogen sulfide, hydrogen cyanide, cysteine, etc., it is possible to reduce the oxidized sulfhydryl group and restore the preparation to a point near its original activity. Using the methods of Balls and Hoover (1) and of Balls, Swenson, and Stuart ($), the activity of the various preparations was determined on the inactive as well as the activated samples. Some of the samples were collected by the author, others were from local known sources; all were prepared and kept under identical conditions. Two samples of foreign origin were also used for comparison. Each sample was dissolved in water and activated with twice its weight of cysteine hydrochloride (in solution a t pH 5.0) for 60 minutes a t 40” C. The results were obtained as shown in Table I. It is unfortunate that the methods used in the assay of preparations 1-7 when first made, were descriptive only of the activity and not of the total enzyme content after suitable activation. No figures are now available for these early samples, but from past experience it appears that they would have compared a t the time of preparation with the present sample 8. The table shows that the first change in a papain preparation with age is inactivation, accompanied by a loss of the sulfhydryl substance that reacts with nitroprusside, but without the destruction of the enzyme. This, however, is followed
by a gradual loss of proteolytic power even in the presence of cysteine. It must therefore be concluded that the enzyme is slowly inactivated and even more slowly destroyed on exposure to air in the dry state. ThBLE
1
Sample Date Milk Clottinga Alcoholic Titrationb Origin No. Obtained Inactive Bctivated Inactive Activated Hawaii 1 0.43 Nov., 1931 0 00 0.18 0.40 0.44 2 J u n e , 1932 0 00 0.19 0.50 0.46 3 Aug., 1932 0 00 0.22 0.65 0.37 4 April, 1934 0.07 0.18 0.55 0.43 5 Aug., 1934 0 00 0.24 0.50 0.48 April, 1936 0 15 0.30 0.50 6 0,49 7 June, 1936 0 22 0.32 0.40 2.85 2 50 8 April 1937 1.80 1.80 0.43 Ceylon 9 Oot.,’1936 0 00 0.35 0.40 0.45 S. E. Africa 10 Feb., 1937 0 36 0.35 0.35 a The unit is t h e amount of enzyme required t o clot 10 cc. of a s t a n d a r d milk meoaration in 1 minute a t 40” C.: l/(et) units uer mg., where e = enzymes;mg t = time, min. b T h e prot:in digestion observed on casein after 20 minutes a t 40’ C b y alcoholic titration. The’cc. of 0.1 N KOH divided b y t h e mg. of sa&e acted upon.
Frank T. Dillingham, Unithe investigation and supplys. Acknowledgment is also due
erature Cited (2) Balls, A. K., Swenson, T. L., and Stuart, L. S., J. Assoc. Oficial A g r . Chem., 18, 140 (1935). RECEIVDD June 7, 1937.
