scholarly journals THE KINETICS OF ENZYME REACTIONS: SCHÜTZ'S LAW

1930 ◽  
Vol 13 (3) ◽  
pp. 323-334 ◽  
Author(s):  
E. A. Moelwyn-Hughes ◽  
J. Pace ◽  
W. C. M. Lewis
Keyword(s):  
Experimental Results ◽  
Mass Action ◽  
Law Of Mass Action ◽  
Enzyme Reactions ◽  
Adsorption Theory ◽  
The Law ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Tryptic Hydrolysis ◽  
Made In

1. A review of the applicability of Schütz's Law to enzymic reactions is given. 2. The theoretical deductions of the Law, (a) on the basis of the law of mass action, (b) on the basis of the adsorption theory, are given and the significance of the assumptions made in these deductions pointed out. 3. It is shown that the true critical increment for an enzymic reaction is equal to twice the critical increment calculated from the Schütz constant ks, if the heat of decomposition of the enzyme-products complex be neglected. 4. Experiments are described on the tryptic hydrolysis of casein at 30°C. and 404C. The foregoing considerations are applied to the experimental results obtained.

scholarly journals THE INFLUENCE OF THE SUBSTRATE CONCENTRATION ON THE RATE OF HYDROLYSIS OF PROTEINS BY PEPSIN

1920 ◽  
Vol 2 (6) ◽  
pp. 595-611 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Relative Rate ◽  
Total Concentration ◽  
Mass Action ◽  
Protein Solutions ◽  
Law Of Mass Action ◽  
Active Mass ◽  
Homogeneous Solutions ◽  
Rate Of Hydrolysis ◽  
The Law ◽  
Hydrolysis Of

1. It is pointed out that the apparent exceptions to the law of mass action found in enzyme reactions may be found in catalytic reactions in strictly homogeneous solutions. 2. These deviations in the rate of reaction from the law of mass action may be explained by the hypothesis that the active mass of the reacting substances is not directly proportional to the total concentration of substance taken. 3. In support of this suggestion it is shown that for any given concentration of pepsin the relative rate of digestion of concentrated and of dilute protein solutions is always the same. If the rate of digestion depended on the saturation of the surface of the enzyme by substrate the relative rate of digestion of concentrated protein solutions should increase more rapidly with the concentration of enzyme than that of dilute solutions. This was found not to be true, even when the enzyme could not be considered saturated in the dilute protein solutions. 4. The rate of digestion and the conductivity of egg albumin solutions of different concentration were found to be approximately proportional at the same pH. This agrees with the hypothesis first expressed by Pauli that the ionized protein is largely or entirely the form which is attacked by the enzyme. 5. The rate of digestion is diminished by a very large increase in the viscosity of the protein solution. This effect is probably a mechanical one due to the retardation of the diffusion of the enzyme.

scholarly journals DOES THE KINETICS OF TRYPSIN DIGESTION DEPEND ON THE FORMATION OF A COMPOUND BETWEEN ENZYME AND SUBSTRATE

1922 ◽  
Vol 4 (5) ◽  
pp. 487-509 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Experimental Evidence ◽  
Substrate Concentration ◽  
Relative Velocity ◽  
Mass Action ◽  
Law Of Mass Action ◽  
Rate Of Hydrolysis ◽  
Gelatin Concentration ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Substrate Concentrations

1. The velocity of hydrolysis of gelatin by trypsin increases more slowly than the gelatin concentration and finally becomes nearly independent of the gelatin concentration. The relative velocity of hydrolysis of any two substrate concentrations is independent of the quantity of enzyme used to make the comparison. 2. The rate of hydrolysis is independent of the viscosity of the solution. 3. The percentage retardation of the rate of hydrolysis by inhibiting substances, is independent of the substrate concentration. 4. There is experimental evidence that the enzyme and inhibiting substance are combined to form a widely dissociated compound. 5. If the substrate were also combined with the enzyme, an increase in the substrate concentration should affect the equilibrium between the enzyme and the inhibiting substance. This is not the case. 6. The rate of digestion of a mixture of casein and gelatin is equal to the sum of the rates of hydrolysis of the two substances alone, as it should be if the rate is proportional to the concentration of free enzyme. This contradicts the saturation hypothesis. 7. If the reaction is followed by determining directly the change in the substrate concentration, it is found that this change agrees with the law of mass action; i.e., the rate of digestion is proportional to the substrate concentration.

scholarly journals THE INACTIVATION OF TRYPSIN

1922 ◽  
Vol 4 (3) ◽  
pp. 245-260 ◽  
Author(s):  
John H. Northrop
Keyword(s):  
Trypsin Inhibitor ◽  
Relative Concentration ◽  
Experimental Results ◽  
Mass Action ◽  
Ion Concentration ◽  
Appreciable Amount ◽  
Law Of Mass Action ◽  
Hydrogen Ion Concentration ◽  
Rate Of Hydrolysis ◽  
The Law

1. A study has been made of the equilibrium existing between trypsin and the substances formed in the digestion of proteins which inhibit its action. 2. This substance could not be obtained by the hydrolysis of the proteins by acid or alkali. It is dialyzable. 3. The equilibrium between this substance (inhibitor) and trypsin is found to agree with the equation, trypsin + inhibitor ⇌ trypsin-inhibitor The equilibrium is reached instantaneously and is independent of the substrate concentration. If it be further assumed that the rate of hydrolysis is proportional to the concentration of the free trypsin and that the equilibrium conforms to the law of mass action, it is possible to calculate the experimental results by the application of the law of mass action. 4. The equilibrium has been studied by varying (a) the concentration of the inhibiting substance, (b) the concentration of trypsin, (c) the concentration of gelatin, and (d) the concentration of trypsin and inhibitor (the relative concentration of the two remaining the same). In all cases the results agree quantitatively with those predicted by the law of mass action. 5. It was found that the percentage retarding effect of the inhibiting substance on the rate of hydrolysis is independent of the hydrogen ion concentration between pH 6.3 and 10.0. 6. The fact that the experimental results agree with the mechanism outlined under 3, is contrary to the assumption that any appreciable amount of trypsin is combined with the gelatin at any one time; i.e., the velocity of the hydrolysis must depend on the time required for such a compound to form rather than for it to decompose. 7. The experiments may be considered as experimental proof of the validity of Arrhenius' explanation of Schütz's rule as applied to trypsin digestion. 8. Inactivated trypsin does not enter into the equilibrium.

Corn Oil in Atherosclerotic Dementia

1962 ◽  
Vol 108 (453) ◽  
pp. 229-231
Author(s):  
H. Dale Beckett
Keyword(s):  
Serum Cholesterol ◽  
Corn Oil ◽  
Cerebral Arteries ◽  
Mass Action ◽  
Law Of Mass Action ◽  
Lipoprotein Complex ◽  
The Law ◽  
Made In

In order to explore the possibility of there occurring, in accordance with the Law of Mass Action, a reversal of the deposition of the cholesterol-lipoid-lipoprotein complex (Bevans et al., 1951), in the walls of cerebral arteries of atherosclerotic dements following a reduction in serum cholesterol, a study was made in March 1959 of changes that were shown in the behaviour of six such patients compared with six senile dements and four schizophrenics following the intake of large quantities of corn oil (Keys, 1956; Anderson et al., 1957).

The Law of Mass Action

2001 ◽  
pp. 121-128
Author(s):  
Bruce Hannon ◽  
Matthias Ruth
Keyword(s):  
Mass Action ◽  
Law Of Mass Action ◽  
The Law

scholarly journals On the Mathematics of the Law of Mass Action

2014 ◽  
pp. 3-46 ◽  
Author(s):  
Leonard Adleman ◽  
Manoj Gopalkrishnan ◽  
Ming-Deh Huang ◽  
Pablo Moisset ◽  
Dustin Reishus
Keyword(s):  
Mass Action ◽  
Law Of Mass Action ◽  
The Law

The Law of Mass Action

1994 ◽  
pp. 73-79
Author(s):  
Bruce Hannon ◽  
Matthias Ruth
Keyword(s):  
Mass Action ◽  
Law Of Mass Action ◽  
The Law

On the mechanistic foundation and limit of Liebig’s law of the minimum

2021 ◽  
Author(s):  
Jinyun Tang ◽  
William Riley
Keyword(s):  
Additive Model ◽  
Additive Models ◽  
Mass Action ◽  
Substrate Uptake ◽  
Law Of Mass Action ◽  
Growth Data ◽  
Biological Growth ◽  
Elemental Stoichiometry ◽  
The Law ◽  
Parameter Values

<p>In ecosystem biogeochemistry, Liebig’s law of the minimum (LLM) is one of the most widely used rules to model and interpret biological growth. Although it is intuitively accepted as being true, its mechanistic foundation has never been clearly presented. We here first show that LLM can be derived from the law of mass action, the state of art theory for modeling biogeochemical reactions. We further show that there are (at least) another two approximations (the synthesizing unit (SU) model and additive model) that are more accurate than LLM in approximating the law of mass action. We then evaluated the LLM, SU, and additive models against growth data of algae and plants. For algae growth, we found all three models are equally accurate, albeit with different parameter values. For plants, LLM failed to accurately model one dataset, and achieved equally good results for other datasets with very different parameters. We also find that LLM does not allow flexible elemental stoichiometry, which is an oft-observed characteristic of plants, when an organism’s growth is modeled as a function of substrate uptake flux. In summary, we caution the use of LLM for modeling biological growth if one is interested in representing the organisms’ capability in adapting to different nutrient conditions.   </p> <p><br /><br /></p>

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