This page documents similarities between Comprehensive Enzyme Kinetics, by Vladimir Leskovac (Kluwer Academic/Plenum Publishers, New York, 2003) and Fundamentals of Enzyme Kinetics (2nd edition), by Athel Cornish-Bowden (Portland Press, London, 1995).
Comprehensive Enzyme Kinetics, by Vladimir Leskovac, was published in 2003 by Kluwer Academic/Plenum Publishers, New York. It presents numerous similarities with Fundamentals of Enzyme Kinetics, by Athel Cornish-Bowden, which was published in 1995 in its 2nd edition (with an earlier edition in 1979 and a later one in 2004). These similarities are most evident in Chapters 2 and 3 of Comprehensive Enzyme Kinetics, but are also noticeable elsewhere. The examples listed here are for illustration only, and the list is not intended to be complete.
In fairness to Vladimir Leskovac, it must be said that he does not accept that he is in any way at fault. His comments may be found below. Nonetheless, his publishers do not agree with him, and their public apology is shown below.
| Leskovac, 2003 | Cornish-Bowden, 1995 |
|---|---|
| Chapter 2 | |
| A chemical reaction can be classified either according to its molecularity or according to its order. The molecularity defines the number of molecules that are altered in the reaction. (p. 11) | A chemical reaction can be classified either according to its molecularity or according to its order. The molecularity defines the number of molecules that are altered in the reaction. (p. 1) |
| For a simple reaction that consists of a single step, or for each step in a complex reaction, the order is usually the same as the molecularity. However, many chemical reactions consist of sequences of unimolecular and bimolecular steps and the molecularity of the complete reaction need not be the same as its order. Complex chemical reactions often have no meaningful order, as the rate often cannot be expressed as a product of concentration terms. This is almost universal in enzyme kinetics, and even the simplest enzyme-catalyzed reactions do not have simple orders. Nevertheless, the concept of order is important for understanding enzyme kinetics, because the individual steps in enzyme-catalyzed reactions nearly always do have simple orders, usually being first or second order. (pp. 11–12) | For a simple reaction that consists of a single step, or for each step in a complex reaction, the order is usually the same as the molecularity. However, many reactions consist of sequences of unimolecular and bimolecular steps, and the molecularity of the complete reaction need not be the same as its order. Indeed, a complex reaction often has no meaningful order, as the rate often cannot be expressed as a product of concentration terms. As we shall see in later chapters, this is almost universal in enzyme kinetics, and even the simplest enzyme-catalysed reactions do not have simple orders. Nonetheless, the concept of order is important for understanding enzyme kinetics, because the individual steps in enzyme-catalysed reactions nearly always do have simple orders, usually being first or second order. (pp. 1–2) |
| It is important to note that the constant of integration α was included in this derivation, evaluated and found to be non-zero; when the kinetic equations are integrated, the constants of integration are rarely found to be zero. (p. 12) | It is important to note that the constant of integration α was included in this derivation, evaluated and found to be non-zero. Constants of integration must always be included and evaluated when integrating kinetic equations; they are rarely found to be zero. (p. 3) |
| Termolecular reactions, such as A + B + C —> P do not usually consist of a single trimolecular step, and consequently they are not usually third order. Instead, the reaction is likely to consist of two or more elementary steps, such as A + B —> X followed by X + C —> P. If one step in such a reaction is much slower than the others, the rate of the complete reaction is equal to the rate of the slow step, which is accordingly known as the rate-limiting step. If there is no clearly defined rate-determining step the rate equation is likely to be complex and to have no integral order. (pp. 13–14) | Trimolecular reactions, such as A + B + C —> P + ..., do not usually consist of a single trimolecular step, and consequently they are not usually third order. Instead the reaction is likely to consist of two or more elementary steps, such as A + B —> X followed by X + C —> P. If one step in such a reaction is much slower than the others, the rate constant of the complete reaction is equal to the rate constant of the slow step, which is accordingly known as the rate-determining (or rate-limiting) step. If there is no clearly defined rate-determining step the rate equation is likely to be complex and to have no integral order. (p. 4) |
| Some reactions are observed to be of zero order, that is, the rate is found to be constant, independent of the concentration of reactants. If a reaction is of zero order with respect to only one reactant, this may simply mean that the reactant enters the reaction after the rate-limiting step. However, some reactions are of zero order overall, that is, independent of all reactant concentrations; such reactions are invariably catalyzed reactions and occur if every reactant is present in such large excess that the full potential of the catalyst is realized. Zero-order kinetics occur in enzyme-catalyzed reactions when the substrate concentrations are saturating. (p. 14) | Some reactions are observed to be of zero order, i.e. the rate is found to be constant, independent of the concentration of reactant. If a reaction is zero order with respect to only one reactant, this may simply mean that the reactant enters the reaction after the rate-determining step. However, some reactions are zero-order overall, i.e. independent of all reactant concentrations. Such reactions are invariably catalysed reactions and occur if every reactant is present in such large excess that the full potential of the catalyst is realized. Zero-order kinetics are common in enzyme-catalysed reactions as the limit at very high reactant concentrations. (p. 5) |
| The simplest way to determine the order of reaction is to measure v at different concentrations A of the reactant. Then, a plot of log v against log A gives a straight line with the slope equal to the order of reaction. If there are more reactants, it is useful to know the order with respect to each reactant. This can be found by altering the concentration of each reactant separately, keeping the other concentrations constant; then the slope of the line will be equal to the order with respect to the variable reactant. For example, if the reaction is second-order in A and first-order in B, v = kA2B; then log v = log k + 2log A + log B. Hence a plot of log v against log A (with B held constant) will have a slope of 2, and a plot of log v against log B (with A held constant) will have a slope of 1. These plots are illustrated in Figure 1.1. It is important to realize that if the rates are determined from the slopes of the progress curve (i.e., a plot of concentration against time), the concentrations of all reactants will change. Therefore, if valid results are to be obtained, the constant reactant must be in large excess at the start of the reaction, so that the changes in its concentration are insignificant. (p. 14) | The simplest means of determining the order of a reaction is to measure the rate v at different concentrations
a of the reactants. Then a plot of log v against log a gives a straight line with slope
equal to the order. If all the reactant concentrations are altered in a constant ratio, the slope of the line is the overall order.
It is useful to know the order with respect to each reactant, however, and this can be found by altering the concentration
of each reactant separately, keeping the other concentrations constant. Then the slope of the line will be equal to the order
with respect to the variable reactant. For example, if the reaction is second-order in A and first-order in B,
v = ka2b; then log v = log k + 2log a + log b.
Hence a plot of log v against log a (with b held constant) will have a slope of 2,
and a plot of log v against log b (with a held constant) will have a slope of 1. These plots
are illustrated in Figure 1.1. It is important to realize that if the rates are determined from the slopes of the progress curve
(i.e. a plot of concentration against time), the concentrations of all the reactants will change. Therefore, if valid results are
to be obtained, either the initial concentrations of the reactants must be in stoicheiometric ratio, in which event the overall
order will be found, or (more usually) the constantreactants must be in large excess at the start of the reaction, so that the changes in their concentrations are insignificant. (p. 5) |
| Many reactions are first order in each reactant, and in these cases it is often possible to carry out the reaction under pseudo-first-order conditions overall, by keeping every reactant except one in large excess. Thus, in many practical situations, the problem of determining a rate constant can be reduced to the problem of determining a first-order rate constant. (p. 15) | Very many reactions are first-order in each reactant, and in these cases it is often possible to carry out the reaction under pseudo-first-order conditions overall by keeping every reactant except one in large excess. Thus, in many practical situations, the problem of determining a rate constant can be reduced to the problem of determining a first-order rate constant. (p. 9) |
| Guggenheim (1926) pointed out a major objection to this plot, that it depends very heavily on an accurate determination of A0 or Pinf. (p. 15) | Guggenheim (1926) pointed out a major objection to this plot, that it depends very heavily on an accurate value of pinf. (p. 10) |
| From the earliest studies of reaction rates, it has become evident that they are profoundly influenced by temperature. Harcourt (1867) established a well-known rule of thumb that the rates of many reactions approximately doubled for each 10°C rise in temperature. The early studies of van’t Hoff (1884) and Arrhenius (1889) form the starting point for all modern theories of the temperature dependence of equilibrium and rate constants. Van’t Hoff and Arrhenius attempted to find quantitative relationships between y temperature and equilibrium constants by comparing kinetic observations with the known properties of these constants. Any equilibrium constant K varies with the absolute temperature T in accordance with the van’t Hoff law. (p. 19) | From the earliest studies of reaction rates, it has been evident that they are profoundly influenced by temperature. The most elementary consequence of this is that the temperature must always be controlled if meaningful results are to be obtained from kinetic experiments. However, with care, one can use temperature much more positively and, by carrying out measurements at several temperatures, one can deduce important information about reaction mechanisms. The studies of van’t Hoff (1884) and Arrhenius (1889) form the starting point for all modern theories of the temperature dependence of rate constants. Harcourt (1867) had earlier noted that the rates of many reactions approximately doubled for each 10°C rise in temperature, but van’t Hoff and Arrhenius attempted to find a more exact relationship by comparing kinetic observations with the known properties of equilibrium constants. Any equilibrium constant K varies with the absolute temperature T in accordance with the van’t Hoff equation. (p. 11) |
| In an aqueous environment, [H+] varies from about 1 M to about 10–14 M. This enormous range of concentrations was reduced by Sørensen (1909) to more manageable proportions by the use of a logarithmic scale: pH = –log [H+]. (pp. 24-25) | In aqueous chemistry, [H+] varies from about 1 M to about 10–14 M, an enormous range that is commonly decreased to more manageable proportions by the use of a logarithmic scale, pH = –log [H+]. (p. 179) |
| Chapter 3 | |
| The earliest studies of rates of enzyme-catalyzed reactions appeared in the scientific literature in the latter part of the nineteenth century (Wurz (sic), 1880; O’Sullivan & Thompson (sic), 1890; Fischer, 1894; Brown, 1882, 1902; Henri, 1902). At that time, no enzyme was available in a pure form, methods of assay were primitive, and the use of buffers to control pH had not been introduced. Moreover, it was customary to follow the course of the reaction over a period of time, in contrast to the usual modern practice of measuring initial reaction rates at various different substrate concentrations, which gives results that are much easier to interpret. (p. 31) | The rates of enzyme-catalysed reactions were first studied in the latter part of the nineteenth century. At that time, no enzyme was available in a pure form, methods of assay were primitive, and the use of buffers to control pH had not been introduced. Moreover, it was customary to follow the course of the reaction over a period of time, in contrast to the more usual modern practice of measuring initial rates at various different substrate concentrations, which gives results that are easier to interpret. (p. 19) |
| Many of the early studies were conducted with enzymes from fermentation, particularly invertase, which catalyzes the hydrolysis of sucrose to monosaccharides D-glucose and D-fructose (p. 31) | Most of the early studies were concerned with enzymes from fermentation, particularly invertase, which catalyses the hydrolysis of sucrose: sucrose + water —> glucose + fructose (p. 19) |
| With the introduction of the concept of hydrogen ion concentration, expressed by the logarithmic scale of pH (Sørensen, 1909), Michaelis and Menten (1913) realized the necessity for carrying out definitive experiments with invertase. They controlled the pH of the reaction medium by using acetate buffer, allowed for the mutarotation of the product and they measured initial reaction rates at different substrate concentrations. (p. 31) | With the introduction of the concept of hydrogen-ion concentration, expressed by the logarithmic scale of pH (Sørensen, 1909), Michaelis and Menten (1913) realized the necessity of carrying out definitive experiments with invertase. They controlled the pH of the reaction by the use of acetate buffers, they allowed for the mutarotation of the product and they measured initial rates of the reaction at different substrate concentrations.(p. 21) |
| Michaelis and Menten are regarded as the founders of modern enzyme kinetics due to the definitive nature of their experiments and the viability of their kinetic theory. (p. 31) | Because of the definitive nature of their experiments, which have served as a standard for most subsequent enzyme-kinetic measurements, Michaelis and Menten are regarded as the founders of modern enzymology. (p. 22) |
| Invertase proved to be a true catalyst, as it was not destroyed or altered in the reaction and it was still active after catalyzing the hydrolysis of 100,000 times its weight of sucrose. The thermal stability of the enzyme was much greater in the presence of its substrate, sucrose, than in its absence; this striking fact indicated that the invertase enters into combination with the sugar, which protects the enzyme from inactivation. (p. 32) | Invertase proved to be a true catalyst, as it was not destroyed or altered in the reaction (except
at high temperatures), and a sample was still active after catalysing the hydrolysis of 100 000 times its
weight of sucrose. Finally, the thermal stability of the enzyme was much greater in the presence of its substrate
than in its absence: Invertase when in the presence of cane sugar [i.e. sucrose] will stand a temperature fully 25°C greater than in its absence. This is a very striking fact, and, as far as we can see, there is only one explanation of it, namely the invertase enters into combination with the sugar.(pp. 19–20) |
| The formulation of Michaelis and Menten, which treats the first step of enzyme catalysis as an equilibrium (Eq. (3.4)), makes unwarranted and unnecessary assumptions about the rate constants (Eq. (3.3)). (p. 34) | The formulation of Michaelis and Menten, which treats the first step of enzyme catalysis as an equilibrium, and that of Van Slyke and Cullen, which treats it as irreversible, both make unwarranted and unnecessary assumptions about the magnitudes of the rate constants. (p. 23) |
| All enzymatic reactions are in principle reversible, in a sense that significant amounts of both substrates and products exist in the equilibrium mixture (Alberty, 1959; Cleland, 1970; Plowman, 1972). Therefore, it is evident that the Michaelis–Menten and Briggs–Haldane mechanisms are incomplete, and that allowance must be made for the reverse reaction. (p. 36) | All reactions are reversible in principle, and many of those of importance in biochemistry are also reversible in practice, in the sense that significant amounts of both substrates and products exist in the equilibrium mixture. It is evident, therefore, that the Michaelis–Menten mechanism, as given, is incomplete, and that allowance should be made for the reverse reaction. (p. 37) |
| Chapter 4 | |
| In principle, the steady-state rate equation for any enzyme mechanism can be derived in the same way as that for the reversible monosubstrate Michaelis–Menten mechanism. What we need is to write down expressions for the rates of change of concentrations of all the intermediates, set them equal to zero and solve the simultaneous equations that result. In practice, however, this method is extremely laborious and liable to error for all but the simplest monosubstrate mechanisms. (p. 55) | In principle, the steady-state rate equation for any mechanism can be derived in the same way as that for the two-step Michaelis–Menten mechanism: first write down expressions for the rates of change of concentrations of all but one of the enzyme forms; next set them all to zero; write down an additional equation to express the fact that the sum of all these concentrations is constant; finally solve the simultaneous equations that result. In practice this method is extremely laborious and liable to error for all but the simplest mechanisms. (p. 73) |
| Cha (1968) has described a method for analyzing mechanisms that contain steps at equilibrium that is much simpler than the complete King–Altman analysis because each group of enzyme forms at equilibrium can be treated as a single species. (p. 65) | Cha (1968) has described a method for analysing mechanisms that contain steps at equilibrium that is much simpler than the full King–Altman analysis because each group of enzyme forms at equilibrium can be treated as a single species. (p. 85) |
| The derivation of a rate equation, whether by the method of King and Altman or in any other way, is a purely mechanical process. As such it is ideal for computer implementation, and a number of computer programs for deriving rate equations have been described (Rhoads & Pring, 1968; Hurst, 1964, 1969; Fisher & Schultz (sic), 1969; Rudolph & Fromm, 1971; Kinderlerer & Ainsworth, 1976; Cornish-Bowden, 1977, Fromm, 1979; Lam, 1981; Ishikawa et al., 1988; Runyan & Gunn, 1989; Varon et al., 1997). (p. 70) | The derivation of a rate equation, whether by the method of King and Altman or in any other way, is a purely mechanical process, and success or failure depends on the avoidance of mistakes rather than on making correct intellectual decisions about how to proceed at any point. As such it is ideal for computer implementation, and a number of computer programs for deriving rate equations have been described (e.g. Rhoads and Pring, 1968; Hurst, 1967, 1969; Fisher and Schulz, 1969; Rudolph and Fromm, 1971; Kinderlerer and Ainsworth, 1976; Cornish-Bowden, 1977). (p. 89) |
| Chapter 13 | |
| It is obvious that all living organisms have a need for a high degree of control over metabolic processes so as to permit orderly change without precipitating unwanted progress towards thermodynamic equilibrium. (p.243) | It is obvious that all living organisms require a high degree of control over metabolic processes so as to permit orderly change without precipitating catastrophic progress towards thermodynamic equilibrium. (p. 203) |
| Chapter 15 | |
| The thermodynamic treatment for the temperature dependence of simple chemical reactions, discussed in Chapter 2 (Section 2.6), applies equally to enzyme-catalyzed reactions, but in practice several complications arise that must be properly understood if any useful information is to be obtained from temperature-dependence studies of enzyme reactions. (p. 317) | In principle, the theoretical treatment discussed in Section 1.5 of the temperature dependence of simple chemical reactions applies equally to enzyme-catalysed reactions, but in practice there are several complications that must be properly understood if any useful information is to be obtained from temperature-dependence measurements. (pp. 193–194) |
| First, almost all enzymes become denatured if they are heated much above physiological temperatures, and the conformation of the enzyme is altered, often irreversibly, with loss of catalytic activity. (p. 317) | First, almost all enzymes become denatured if they are heated much above physiological temperatures, and the conformation of the enzyme is altered, often irreversibly, with loss of catalytic activity. (p. 194) |
| Chapter 16 | |
| Study of the initial rates of bisubstrate and trisubstrate reactions in both directions, and in the presence and absence of products, will usually eliminate many possible reaction pathways and give a reasonably good idea of the main features of the mechanism, but it will not usually reveal the existence of minor alternative pathways. (p. 329) | Study of the initial rates of multiple-substrate reactions in both forward and reverse directions, and in the presence and absence of products, will usually eliminate many possible reaction pathways and give a good idea of the gross features of the mechanism, but it will not usually reveal the existence of any minor alternative pathways if these contribute negligibly to the total rate. (p. 160) |
| Even if a clear mechanism does emerge from initial rate and product inhibition studies, it is valuable to confirm its validity independently. The important technique of isotope exchange can often satisfy these requirements. (p. 329) | Even if a clear mechanism does emerge from initial-rate and product-inhibition experiments, it is valuable to be able to confirm its validity independently. The important technique of isotope exchange can often satisfy these requirements. (p. 160) |
| In a chemical reaction, even if it at equilibrium, when its net rate is zero by definition, the unidirectional rates through steps or groups of steps can be measured by means of isotopic tracers. (p. 329) | Even if a chemical reaction is at equilibrium, when its net rate is zero by definition, the unidirectional rates through steps or groups of steps can be measured by means of isotopic tracers. (pp. 160–161) |
Vladimir Leskovac does not consider that the similarity between the two books goes beyond borrowing of some of my grammar, but readers may make their own judgement. Here is an unsolicited comment that he wrote at the beginning of January 2005 (at which time I had had no direct contact with him, though Kluwer had certainly heard from Portland Press, and he had presumably heard from Kluwer):
Novi Sad, January 3, 2005.
Dear Dr. Cornish-Bowden:
You are making a lot of trouble to all of us with
your infringement
claims. This is not fair.
Large portions of my textbook Comprehensive
Enzyme Kinetics
are based on the research work and
the scientific ideas of leading kineticists: WW Cleland,
H Fromm, DB Northrop, RL Schowen, and BV Plapp.
All these people examined my book in its manuscript
phase, and none of them had any objections. On the
contrary, all of them have corrected many serious errors
in judgment I have made in the manuscript, and thus
improved the manuscript considerably. I salute them all!
This is the true spirit of science, which is cooperation
and not the confrontation.
On the other hand, I have taken none of your research work or your scientific ideas into my book, but merely borrowed some of your grammar, because English is not my native language. The critical overlapping places, especially in Chapters 2 and 3, are a common knowledge, and I could pick it up from any of the dozen textbooks in chemistry, physical chemistry, or biochemistry. Therefore, your intervention came as a surprise to me. I do apologize for the overlaps.
My book is entirely different from yours and it is not a competition to your book in any way. On the contrary, these two books are very much complementary. I want to think that your book will serve as a textbook for students, while mine will sit in departmental libraries as a handbook; so, they will be complementary.
In the future, we shall certainly correct the disputed places in my book and remove any similarities with your text. This, however, will require some time, because it involves the technical problems.
For the time being, I sincerely hope that you will act in the spirit of these festive days, and show a good will in the New Years Day. Please leave my book alone and let it swim on its own in the technical literature, at least for the time being. You may be proud of your own book, to which I wish all success. In this spirit, I remain sincerely yours,
Prof. Vladimir Leskovac
Faculty of Technology
Bulevar Cara Lazara 1
YU-21000 Novi Sad
Y U G O S L A V I A
Fax: ++381-21-450-130
Vladimir Leskovac’s publishers do not see the matter in the same light as he does, and their public apology appeared in The Biochemist 27, page 54 (April 2005).
