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Showing papers in "Journal of the American Chemical Society in 1934"


Journal ArticleDOI
TL;DR: On the basis of the assumed theory the rate of the observed reaction is directly proportional to the concentration of the enzyme-substrate compound, where (E:l = (ES).
Abstract: On the basis of the assumed theory the rate of the observed reaction is directly proportional to the concentration of the enzyme-substrate compound, (ES), a t all values of the concentration of the substrate, (S). It is proportional to (S) only a t low values of (S). The numerical value of the dissociation constant is given by the substrate concentration a t half-maximum velocity, where (E:l = (ES). The equilibrium in equation 1 may be heterogeneous or homogeneous. Hitchcock'\" has pointed

11,349 citations




Journal ArticleDOI
TL;DR: Rice and Herzfeld as discussed by the authors showed that there are certain types of complex mechanisms that lead to simple kinetic behavior, such as a simple splitting of the molecule into ethylene and hydrogen.
Abstract: [Organic decompositions frequently have simple integral orders and it was natural to assume that they occur by simple molecular mechanisms; the ethane pyrolysis, for example, is usually first order, and was thought to occur by a simple splitting of the molecule into ethylene and hydrogen. The discovery by F. Paneth and W. Hofeditz (Ber. B, 62, 1335 (1929)) of the free methyl radical led, however, to the suspicion that this and other radicals are involved in certain organic reactions, and in 1933 F. O. Rice and M. D. Dooley (J. Amer. Chem. Soc.55, 4245 (1933)) demonstrated the presence of free radicals in ethane that was undergoing decomposition. The question that then arose was: how is it possible for a reaction to occur by a complex mechanism and to exhibit simple kinetics ? The paper that is reproduced below is of particular importance in that it shows that there are certain types of complex mechanisms that lead to simple kinetic behaviour. Francis Owen Rice was born in England in 1890 but has lived in the United States since 1919; at the time this paper was written he was an Associate Professor at the John Hopkins University. He was later Chairman of the Chemistry Department at the Catholic University of America, and Chairman of the Chemistry Department of Georgetown University. He has made many pioneering contributions especially in the field of free radical reactions. Karl Ferdinand Herzfeld was born in Vienna in 1892 and has worked in the United States since 1923. At the time this paper was written he was Professor of Physics at the John Hopkins University, later becoming Chairman of the Department of Physics at the Catholic University of America. He has made many important contributions in theoretical physics, particularly in the fields of molecular structure, the solid state and ultrasonics. The Rice-Herzfeld paper is here reproduced in its entirety. The reader should note that most of the numerical values quoted, e.g. for activation energies, now require substantial revision and that some of the mechanisms require modification; the general principles, however, still stand.]

259 citations