COMMUNICATIONS TO THE EDITOR
1514
acting center of the base also cause deviations even within a series of the same charge type.2 I n view of these facts, extreme interest attaches to the accompanying figure, in which catalytic constants4,' for the mutarotation of glucose at 18' are plotted logarithmically against the corresponding catalytic constant^^'^^^^^ for the decomposition of nitramide a t l5', both in aqueous solution. The figure includes all the bases whose behavior in both reactions has been studied. No statistical corrections are made. The straight line has a slope of 2.00.
Vol. GO
(NH3)oOH++ follow the same relationship which holds for the negative bases such as acetate ion. This is particularly startling in the case of Co(NH8)60Hf+, which in the familiar kR ws. K B plot deviates from the carboxylate ion curve by as much as two logarithmic units. It is therefore highly desirable that knowledge of these and other reactions susceptible to general base catalysis be extended to include more bases in common. If the uniqueness of Fig. 1 is upheld by further extension of the data, it implies that the relationship between two series of rate constants for association by bases of protons from two different substrates is more fundamental than the relationship of either series of rate constants to corresponding equilibrium constants. It follows further that deviations which occur in the kB vs. K B relationships must originate in deviations in the relationships between the rate constants for association and dissociation ; this also can be submitted to experimental study. In its amenability to experimental attack, such an empirical approach differs from the theoretical approach embodied in the transition-state method which assumes the fundamental relationship to be between equilibrium constants and then attempts t o derive the connection between rate and equilibrium constants by postulating an equilibrium between initial and transition states, the constant for which can unfortunately not be measured.8 (8) See symposium in Tuans. Favaday Soc., 34, 29ff.(1938).
HELMUTH L. PFLUCER SLATERSVILLE, R. I. RECEIVEDAPRIL25, 1938
-2 -1 0 Log k B glucose mutarotation. Fig. 1.-Plot of log kn for nitramide decomposition against log k B for glucose mutarotation: 1, hetaine3p7; 2, salicylate6"; 5, phenyl3, f o r n ~ a t e ~4, ~ ~benzoate3p4; ; 6, acetate314; 7, propionacetate3"; ate3"; 8, trimethylacetate6t4; 9, quinoline2~'; 10, pyridine2,'; l l , CO(NHI)LOH++6$4, -3
It is immediately apparent that all the points fall reasonably well on the same straight line and that betaine, pyridine, quinoline and even Co(2) Work t o he published by t h e writer. (3) Brilnsted and Pedersen, 2.p h y s i k . Chcm., 108, 185 (1924). ~ 49,2664 (1927). (4) BrOnsted and Guggenhcim, T H IJOURNAL, (6) Br6nst6d and Volqvartz, Z. 9 h y s i k . Chcm., A l a s , 211 (1931). (6) Baughan and Bell, Proc. Roy. Soc. (London), MEA, 464 (1937).
(7) Westheimec. J . Org. C h e w . , 3, 451
(1937).
INFLUENCE OF NICOTINIC ACID ON T H E FERMENTATION METHOD FOR V I T A M m Bi DETERMINATION
Sir : Lohmann and Schuster' have showti that a vitamin B1 pyrophosphate is identical with cocarboxylase. This coenzyme plays an essential part in the series of reactions which produce alcoholic fermentation and, in all probability, was present in the original Harden and Young extracts of cozymase. With regard to our fermentation method for vitamin B1 determination,2 it has been our working hypothesis that vitamin B1, or the aminopyrimidine, is taken inside the (1) K.Lohmann and Ph. Schuster, Biochem. C , 284, 188 (1837). (2) A. S. Schultz, I,. Atkin and C N. Frey, THISJ O U R N A I . . 6 9 , (4 948, (b) 2457 (1937).
June, 193s
COMMUNICATIONS TO THE EDITOR
1515
living cell and there transformed to cocarboxylase or its equivalent. We have considered the possibility that other substances might, on diffusion into the cell, be likewise converted into one of the elements of cozymase, i. e., codehydrase, cophmphorylase or cocarboxylase. Adenylic acid, which is considered to be equivalent to cophosphorylase and which is contained in codehydrase, has been tested and found to be without action. Nicotinic acid which is present in the codefiydrase molecule as the amide shows a certain stimulation.
for bios activity but up t o the present we have obtained no positive results.
(3) A S Schultz, I. Atkin and C N Frey, THIS JOURNAL, 60, 490 (1038).
(1937); (f) Kistiakowsky and Narmi, J . Chem. Physics, 6, 18 (1D:iS) ( 9 ) Kistiakowsky and Wilson, THIS J O U R N A L , 50, 494 (1038).
THE FLEIXHMANN LABORATORIES A . S. S~HULTZ STANDARD BRANDSINCORPORATED L.ATKIN 810 GRANDCONCOURSE C. N. FREY NEWYORK,N. Y . RECEIVED APRIL20, 1938 RESTRICTED INTERNAL ROTATION IN HYDROCARBONS
Sir : In the short time since we presented the first definite conclusionLin favor of the existence of a TABLEI Av. diff. Possihle high potential restricting the internal rotation in due to error in M1 a s p e r 3 hrs nicotinic a v i t €31 ethane, considerable discussion and additional Addition A tests) acid assay evidence2 have appeared in the literature. Most None (standard control mixture) 220 222 220 recently Kistiakowsky and Wilsonzg have satis1 mg nicotinic acid 222 224 224 4-2 factorily summarized the general situation ; how296 295 800 2 gamma vitamin Bi 2 gamma vitamin Bi plus 1 mg ever, certain of their statements appear to be misnicotinic acid 306 308 305 +9 15% leading, particularly in view of new evidence ob4 gamma vitamin Bi 355 353 359 4 gamma vitamin BI plus 1 mg. tained in this Laboratory. nicotinic acid 360 368 362 +7 7% A general though approximate method for conTable I shows how the effect was measured. veniently relating thermodynamic functions and The absolute values obtained cannot be compared potential barriers for various molecules has been with our previous data’ but i t will be observed given.2b It of course should be realized that rethat and correspond reasonably stricting potentials calculated by this method well. This is not a t all surprising since relatively have exact meaning only in connection with the small variations in the vitamin and moisture assumed shape of potential barrier. This, howcontent of the compressed yeast used will affect ever, detracts little from their usefulness in correthe rate of gas production of the controls. A lating a large amount of thermodynamic data besingle pair of measurements, either zero and 4 cause the same assumed shape of potential barrier gamma or 2 and 4 gamma, wlll automatically will have been used throughout. Indeed, such a correct for these variations, and from then on the correlation of the various thermodynamic data as same pound of yeast may be used until i t is ex- yet available was made, which showed the general hausted, with no more than a single control ( 2 or applicability and correctness of accurate entropies obtained through the third law of thermodynam4 gamma) in each run. Increasing amounts of nicotinic acid up to 50 ics. Kistiakowsky and Wilson, however, assert rng. did not show an increased effect. The amide that the selection of the magnitude of some of the of nicotinic acid was tested but did not show any potentials was “arbitrary” and that “without the greater activity. The effect of nicotinic acid knowledge of the laws of force responsible for the though small is significant and the resulting pos- hindrance of internal rotation” calculations such sible error in a vitamin assay should be eliminated as these are “rather meaningless. . . .I’ It is of if possible. This is readily done by including course true that in a few cases potential barriers nicotinic acid in all tests. Since large amounts were estimated ; however, the only assumption show no further stimulation the addition of 1 mg. made was the almost axiomatic one that the reof nicotinic acid removes the possible source of striction of rotation about a given C-C bond is error. The negligible effect of added nicotinic related to the position and character of the groups acid on the blank determination is interesting and (1) Kemp and Pitzer, J . Chem. Physics, 4, 749 (1936); THIS 69, 276 (1937). may account for the general failure to observe this JOURNAL, (2) (a) Howard, Phys. Rev., 61, 53 (1937); J . Chcm. Physics, 6 , effect heretofore. Following our work on vita- 442, 451 (1937); (b) Pitzer, i b i d . , 6, 469, 473 (1937); (c) Bartholome Karwill, N a t u r w i s s . , 26, 476 (1937); (d) Aston, Siller and Mesmin B1 as a bios f a ~ t o r we , ~ tested nicotinic acid and serly, T H I S JOURNAL, 69, 1743 (1937); (e) Kassel, ibid., 69, 274.5 ~
