Haldane

Briggs and Haldane [8] proposed a general mathematieal deseription of enzymatie kinetie reaetion. Their model is based on the assumption that after a short initial startup period, the eoneentration of the enzyme-substrate eomplex is in a pseudo-steady state (PSS). Eor a eonstant volume bateh reaetor operated at eonstant temperature T, and pH, the rate expressions and material balanees on S, E, ES, and P are... 

The interpretations of Michaelis and Menten were refined and extended in 1925 by Briggs and Haldane, by assuming the concentration of the enzyme-substrate complex ES quickly reaches a constant value in such a dynamic system. That is, ES is formed as rapidly from E + S as it disappears by its two possible fates dissociation to regenerate E + S, and reaction to form E + P. This assumption is termed the steady-state assumption and is expressed as... 

A theoretical discussion of the heat pump appeared in the Journal of the Franklin Institute in I 886. T. G. N. Haldane of Scotland comprehensively pursued the application of heat pumps to the heating of buildings after the mid-1920s. Haldane tested air-to-watcr heat pump systems in his home and concluded that... 

Haldane, T. G. N. (1930). The Heat Pump An Economical Method of Producing Low-Grade Heat from Electricity. Journal of the Institution of Electrical Engineers 68 666—675. 

H+], calculation of, 192, see also Hydrogen ion Haber, Fritz, 151 Haber process, 140, 150 Hafnium, oxidation number, 414 Haldane, J. B. S., 436 Half-cell potentials effect of concentration, 213 measuring, 210 standard, 210 table of, 211, 452 Half-cell reactions, 201 Half-life, 416 Half-reaction, 201 balancing, 218 potentials, 452 Halides... 

One reaction scheme that leads to Michaelis-Menten kinetics is known as the Briggs-Haldane scheme. It consists of these reactions ... 

These relationships are identical to Haldane relationships, but unlike the latter, their validity does not derive from a proposed reaction scheme, but merely from the observed hyperbolic dependence of transport rates upon substrate concentration. Krupka showed that these relationships were not obeyed by the set of data previously used by Lieb [64] to reject the simple asymmetric carrier model for glucose transport. Such data therefore cannot be used either to confirm or refute the model. 

Ch.l, Allen Unwin The Biochemistry of Genetics (Haldane, 1954) Ch.4, Penguin Books A Case of Knives (McWilliam, 1988) ... 

Rosthorn, J., Haldane, A., Blackwell, E. Wholey, J. (1986) Small Business Action Kit. Kogan Page, London. 

Subsequently Briggs and Haldane (1925) demonstrated that a similar treatment could be used to describe steady state enzyme velocity as a saturable function of substrate concentration ... 

Haldane, J. B. S. (1930), Enzymes, Longmans, Green. Reprinted by MIT Press, Cambridge (1965). Henri, V. (1903), Lois generates de Taction des diastases, Hermann, Paris. 

Uniform ID systems obtained from 5=1 ions like Ni11 are of particular interest with respect to the experimental investigation of the so-called Haldane s gap, i.e., a quantic gap created between the ground state (5 = 0) and the first excited state of a chain where the local 5-value is an... 

This is, in essence, the modern synthesis of Darwin and Mendel achieved in the 1930s by Ronald Fisher and J. B. S. Haldane. Based on a series of relatively straightforward equations, it also took the study of evolution out of meticulously observed natural history and located it within a more abstract mathematised theory. Indeed, evolution itself came to be defined not in terms of organisms and populations, but as the rate of change of gene frequencies within any given population. One consequence has been a tendency for theoretical evolutionists to retreat further and further into abstract hypotheticals based on computer simulations, and to withdraw from that patient observation of the natural world which so characterised Darwin s own method . 

The additional refinement to the theory, which is essential for the full flowering of evolutionary psychology, was suggested in an often recounted pub comment by Haldane in the 1950s, that he would be prepared to sacrifice his life for two brothers or eight cousins. Because he shared genes in common with his kin, the proportion varying with the closeness of... 

Sarkar, S. (1991), Haldane s solution of the Luria-Delbrixck distribution , Genetics, 127, 224-231. 

Haldane JBS (1928) The Origin of Life. Rationalist Annual 148 3. Reprinted in Science and Human Life, Harper Brothers, New York, 1933 Herrera AA (1942) Science 96 14... 

Stanley Miller at the University of Chicago more than 50 years ago. This experiment (in fact, of course, many were carried out prior to the successful one) is probably as well known as the Wohler synthesis of urea Miller s doctoral supervisor, Harold Urey (winner of the Nobel Prize in 1934), had suggested to Miller that he simulate a reducing primeval Earth atmosphere (as required by the Oparin-Haldane hypothesis) to electrical discharges and see what happens . Urey apparently expected that such an experiment would lead to a huge variety of organic compounds. 

A plot of the initial reaction rate, v, as a function of the substrate concentration [S], shows a hyperbolic relationship (Figure 4). As the [S] becomes very large and the enzyme is saturated with the substrate, the reaction rate will not increase indefinitely but, for a fixed amount of [E], it reaches a plateau at a limiting value named the maximal velocity (vmax). This behavior can be explained using the equilibrium model of Michaelis-Menten (1913) or the steady-state model of Briggs and Haldane (1926). The first one is based on the assumption that the rate of breakdown of the ES complex to yield the product is much slower that the dissociation of ES. This means that k2 tj. 

Conversion rate data obtained under a wide range of operating conditions may be worked out to provide a kinetic expression, most typically expressed according to well established models for bioprocess kinetics first and second order, Monod, Haldane, product-inhibited, etc. 

The general theory of enzyme kinetics is based on the work of L. Michaelis and M. L. Menten, later extended by G. E. Briggs and J. B. S. Haldane.la The basic reactions (E = enzyme, S = substrate, P = product) are shown in equation 2.1 ... 

The kinetics of the general enzyme-catalyzed reaction (equation 10.1-1) may be simple or complex, depending upon the enzyme and substrate concentrations, the presence/absence of inhibitors and/or cofactors, and upon temperature, shear, ionic strength, and pH. The simplest form of the rate law for enzyme reactions was proposed by Henri (1902), and a mechanism was proposed by Michaelis and Menten (1913), which was later extended by Briggs and Haldane (1925). The mechanism is usually referred to as the Michaelis-Menten mechanism or model. It is a two-step mechanism, the first step being a rapid, reversible formation of an enzyme-substrate complex, ES, followed by a slow, rate-determining decomposition step to form the product and reproduce the enzyme ... 

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