1898
COMMUNICATIONS TO THE EDITOR
lowed by acetylation and treatment with sodium bicarbonate then gives D-erythro-triacetoxy-1nitropentene-1, the key compound for the desose synthesis, in 45% yield.
Vol. 71 TABLE I
DEPARTMENT OF CHEMISTRY WASHINGTON UNIVERSITY JOHN C. SOWDEN ST. LOUIS5, MISSOURI RECEIVED APRIL4, 1949
Substance
C
Acetic acid Carbon dioxide Carbon monoxide Ethyl alcohol Methyl alcohol Nitrogen Oxygen n-Propyl alcohol
23.28 9.736 24.85 55.69 54.91 20.31 7.683 50.84
P 3.716 3.857 4 I343 3 774 3.792 3.887 4.053 3.465 I
REVISION OF THE PARACHOR
Further work on the investigation whether or not the revised parachor can eliniinate the parachor The author‘ has recently advanced an inter- anomalies is desirable, but i t is too laborious and pretation of Sugden’s parachor. I n view of the time-consuming for any individual worker. It observation of Ferguson and Kennedy2 that the would be a good idea to have a group of experts index of Macleod’s equation3 is sensibly different working on a cooperative basis and as such the from 4, the need for a revision of the parachor4 forthcoming meeting of the International Union arises. of Pure and Applied Chemistry should provide Sugden’s method of testing Macleod’s equation the necessary opportunity for taking up this work. is misleading as large variations in C appear small INSTITUTE OF TECHNOLOGY by comparing the fourth roots of C. In attempt- LAXMINARAYAN NAGPUR UNIVERSITY M. S. TELANG ing to show that Cl4is nearly constant over wide NAGPUR, INDIA temperature intervals, Sugden6 attributes deviaRECEIVED APRIL13, 1949 tions to experimental errors. A graphical or algebraic test would have shown that the experimental results are satisfactory, justifying the INHIBITION OF UREASE modification of Macleod’s equation as suggested Sir : by Ferguson and Kennedy which is observed by In a recent publication Niemann and Harmon’ the present author t o be applicable right up to the critical temperature. Carbon dioxide, for in- showed that the enzyme urease is inhibited by stance, obeys i t up t o even 1’ below the critical phosphate ions, this inhibition being competitive temperature. Further, the so-called associated with the substrate, urea. Following upon the liquids, methyl, ethyl and n-propyl alcohols and finding of Lumry2 that sulfite inhibits urease and acetic acid obey this modified equation remarkably that this inhibition is responsible for the “abwell a t all temperatures. The substances ordi- normal” temperature dependence of reaction rates narily occurring as gases cited in Table I serve in the urea-urease system^,^ we have studied the to supplement the observations of Ferguson and inhibition by sulfite in detail. Working with high concentrations of urea, a t Kennedy, the data being taken from the “Int. which the rate is zero order in urea, we find that Crit. Tables.”6 Since p is not the same for all substances, this inhibition is first order in sulfite and in ;MC‘/k = P has no natural significance. Hence, enzyme. It appears that both the sulfite and biFerguson and Kennedy2 proposed t o express the sulfite ions are equally effective in causing inhiparachor in the revised form P, = ilfC’’*. But, bition, the equilibrium constant being inversely unfortunately, their paper has not attracted the proportional, however, to hydrogen ion concenattention which it deserves. Sugden6 has stated tration. The data definitely do not fit the that the parachors of lower alcohols and acids hypothesis that bisulfite ions alone are the cause steadily increase with temperature. This of inhibition, as evidenced by Table I. The heat anomaly disappears on taking the revised paraTABLEI chors. The theory postulated by Sidgwick’ t o Temperature 8.5‘ account for the so-called parachor anomaly of A K (Ao - A ) associated liquids is, therefore, unnecessary. AQ
Sir :
L-l
1%
(1) M. S. Telang, THIS JOURNAL. 71, 1883 (1949). (2) A. Ferguson and S. J. Kennedy, Trans. Faraday Soc., 84, 1474 (1936). (3) D.B. Mecleod, ibid., lQ, 38 (1923). (4) S. Sugden, “The Parachor and Valency,” Routledge, London, 1930,p. 30. ( 5 ) S. Sugden, J . Chcn. Soc., 146, 32 (1924); “The Parechor and Valency,” p. 26. (6) In Sugden’s paper,, for benzene at 280”,( D - d ) has been wrongly taken as 0.2305 instead of 0.2854; consequently, C1/k has suddenly shot up. (7) N. V. Sidgwick and N . S. Bayliss, J . Chcm. Soc., 2033
(19301.
pH
(original activity)
6.20 6.50 6.93 7.12 7.55
3.5 4.8 6.5 7.4 7.2
(inhibited ( A O - A ) activity) (A) (HSOa-)
0.77 1.3 2.9 3.4 3.8
63 38 23 14 10
sulfite)(H+)
10.4 8.9 10.5 8.4 7.9 A ~ .9 . 2
x x x x x x
107 107 107
107 107 107
(1) Niemaan and Harmon, J . Bioi. Chem., 177, 601 (1949). ( 2 ) Kistiakowsky and Lumry, THIS JOURNAL, 71, in press (1949). (3) Sizer, J . B i d . Chem., 182, 209 (1940).
May, 1949
COMMUNICATIONS TO THE EDITOR
1899
Tests for halogen in these washed solutions have been negative. The solutions then have been dried, and the solvent ether removed by evaporation a t low temperatures on a vacuum line. Some volatile manganese generally distills with the ether and may be collected in a trap a t -80'. Less volatile ether-soluble manganese compounds remain in the residue. The compounds also are soluble in n-pentane. Manganese is extracted from a n ether solution of manganese carbonyl by aqueous alkali. Acidification of the resulting solution in a stream of carbon monoxide releases a volatile manganese compound which can be collected in a subsequent This may be the Mn(C0)4Ha trap a t -80'. which has been predicted.2 HARVARD CHEMICAL LABORATORY J. F. AMBROSE 12 OXFORD STREET G. B. KISTIAKOWSKY The addition of mercuric chloride t o an ethereal A. G. KRIDL solution of manganese carbonyl results in a slow CAMBRIDGE 38, MASS. evolution of gas and a precipitate containing manRECEIVED APRIL21, 1949 ganese and mercury. Heating the dried precipitate liberates free mercury, leaving a residue containing manganese. This behavior is consistent MANGANESE CARBONYL for a mercuric salt of manganese carbonyl hydride. Sir : The peaks observed for manganese carbonyl in The synthesis of volatile manganese com- the mass spectrometer are strong, occur a t regupounds, believed to be carbonyls of manganese, lar intervals following a pattern similar t o that of has been accomplished by reducing manganese other metal carbonyls, and do not correspond to iodide with Grignard reagent under pressure of any of the predictable impurities The observacarbon monoxide. The general reaction tech- tion of the fragments ~ ~ I ~ ( C OMnz(C0)6+ )~+, and nique has been that described for the preparation Mn2(CO)1+, formed in the spectrometer by elecof chromium carbonyl by Owen, English, Cassidy tron bombardment, indicates the existence of a and Dundon.' dimeric manganese carbonyl but does not define Identification of the volatile manganese com- the formula since i t is not uncommon for the pounds as carbonyls has been made by the obser- parent peak to be absent in a mass spectrometric vation that they behave chemically as would be analysis. Peaks corresponding to Mn+, MnC+, predicted from a consideration of their relation to MnCO+, MnC(C0) +, Mn(CO)zf, MnC(C0)2+, the carbonyls of iron and cobalt, and by mass Mn(C0)3+, and MnC(CO)$+ also have been obspectrometric analyses which show characteris- served. The appearance of the intermediate tic peaks predicted for manganese carbonyl. fragments containing C atoms is typical of the Qualitative tests for manganese in distillation mass spectra of all metal carbonyls investigated fractions, etc., have been made by decomposing so far and will be reported later. the samples with nitric acid and developing the Transparent crystals (containing manganese) permanganate color with the highly specific per- have been isolated by subliming solvent-free masulfate test. terial in a stream of carbon monoxide. The quanThe ethereal solutions from the synthesis reac- tity of material has been small and no pure comtions have been subjected to repeated washings pounds have been identified as yet. with dilute hydrochloric acid and distilled water GENERAL ELECTRIC DALLAST. HURD to remove manganese halide, and unreacted man- RESEARCH W. SENTELL, JR. LAB. GEORGE ganese iodide, and to destroy any organomanga- SCHESECTADY, h7.Y . FRANCIS J. NORTON nese compounds possibly formed in the reaction. RECEIVED APRIL22, 1949
of this reaction is 11,000cal./mole of active centers of the enzyme and is independent of the PH. This value differs considerably from that estimated by Kistiakowsky and Lumry, and is more accurate because of a more direct method of determination and a greatly improved reproducibility of measurements. The inhibition by sulfite, similarly to the inhibition by phosphate ions described by Niemann and Harmon, has been found to be competitive with urea. We also find that certain organic sulfur compounds, such as sodium benzene sulfinate, inhibit the enzyme in the same manner as sulfite ions, and our experiments in this direction are continuing.
(1)
B. B. Owen, et al., THISJOURNAL, 89, 1723 (1947).
(2) Blanchard, Chem. Rev., l l , 35 (1937).
