scholarly journals Enzyme catalysis as a chain reaction

1991 ◽  
Vol 279 (3) ◽  
pp. 855-861 ◽  
Author(s):  
S E Szedlacsek ◽  
R G Duggleby ◽  
M O Vlad
Keyword(s):  
Reaction Mechanism ◽  
Kinetic Mechanism ◽  
Point Of View ◽  
Simple Type ◽  
Chain Reaction ◽  
Proposed Model ◽  
New Type ◽  
A Chain ◽  
Theoretical Considerations ◽  
Classical Mechanism

A new type of enzyme kinetic mechanism is suggested by which catalysis may be viewed as a chain reaction. A simple type of one-substrate/one-product reaction mechanism has been analysed from this point of view, and the kinetics, in both the transient and the steady-state phases, has been reconsidered. This analysis, as well as literature data and theoretical considerations, shows that the proposed model is a generalization of the classical ones. As a consequence of the suggested mechanism, the expressions, and in some cases even the significance of classical constants (Km and Vmax.), are altered. Moreover, this mechanism suggests that, between two successive enzyme-binding steps, more than one catalytic act could be accomplished. The reaction catalysed by alcohol dehydrogenase was analysed, and it was shown that this chain-reaction mechanism has a real contribution to the catalytic process, which could become exclusive under particular conditions. Similarly, the mechanism of glycogen phosphorylase is considered, and two partly modified versions of the classical mechanism are proposed. They account for both the existing experimental facts and suggest the possibility of chain-reaction pathways for any polymerase.

Feasibility of construction of a chemical H2–Cl2laser with a chain reaction mechanism

1981 ◽  
Vol 11 (1) ◽  
pp. 103-105
Author(s):  
A S Bashkin ◽  
N M Gorshunov ◽  
Yu P Neshchimenko ◽  
A N Oraevskiĭ ◽  
A N Shcherbo
Keyword(s):  
Reaction Mechanism ◽  
Chain Reaction ◽  
A Chain

THE MECHANISM OF POLYMERIZATION REACTIONS

1932 ◽  
Vol 7 (1) ◽  
pp. 113-114 ◽  
Author(s):  
William Chalmers
Keyword(s):  
Reaction Mechanism ◽  
Double Bond ◽  
Hydrogen Atoms ◽  
Chain Reaction ◽  
A Chain

Attention is called to an earlier, unpublished writing by the author wherein a chain-reaction mechanism was suggested for all polymerizations leading to macro-molecular products. It is further pointed out that the only scheme of reaction which is compatible with this mechanism is that which involves only the double bond, i.e., the possibility of the changes taking place by the transference of hydrogen atoms is practically excluded.

scholarly journals Study on the virus transmission based on data analysis of confirmed cases of the new-type coronavirus pneumonia in China

2020 ◽  
Author(s):  
Peng Chen
Keyword(s):  
Data Analysis ◽  
Numerical Analysis ◽  
Virus Transmission ◽  
Transmission Mechanism ◽  
Chain Reaction ◽  
Republic Of China ◽  
Exponential Law ◽  
New Type ◽  
A Chain ◽  
Single Exponential

This study was based on the numerical analysis on the number of confirmed cases of new-type coronavirus pneumonia in Wuhan announced by the National Health Commission of the People's Republic of China, and the confirmed cases is collected from 15 January to present (30 January). The analysis results show that during this period, the number of confirmed cases increased strictly according to a single exponential law, indicating that the virus transmission showed a chain reaction. The main conclusion is that the spread of the virus is not only a "human-to-human" transmission, but also that the infectious power of each generation has not changed till to 29 Jan, and the number of people infected has increased tenfold in about 6 days, which are much faster than SARS. Furthermore, the rapid increase in the number of cases suggests that the new virus may have some new transmission channels different from SARS. According to these results, it is suggested to concentrate on studying the new-type coronavirus transmission mechanism and take targeted measures to comprehensively stop the virus infection.

KINETICS OF THE OXIDATION OF URANIUM(IV) BY MOLECULAR OXYGEN IN AQUEOUS PERCHLORIC ACID SOLUTION

1956 ◽  
Vol 34 (10) ◽  
pp. 1419-1427 ◽  
Author(s):  
J. Halpern ◽  
J. G. Smith
Keyword(s):  
Reaction Mechanism ◽  
Acid Solution ◽  
Molecular Oxygen ◽  
Perchloric Acid ◽  
Chain Reaction ◽  
Perchloric Acid Solution ◽  
Aqueous Perchloric Acid ◽  
A Chain ◽  
Kinetics Of ◽  
Considerable Range

The kinetics of the oxidation of uranium(IV) by molecular oxygen in aqueous perchloric acid solution were studied. Over a considerable range of conditions, the results are fitted approximately by the rate law:−d[UIV]/dt = k[UIV] [O2]/[H+], where k ≈ 2 × 1014 exp[−22,000/RT]sec.−1. The reaction is catalyzed by Cu++ and inhibited by small amounts of Ag+ and Cl−. The results are interpreted in terms of a chain reaction mechanism involving UO2+ and HO2 as chain carriers.

scholarly journals A unique mechanism for thiolation of serum albumins by disulphide molecules

2019 ◽  
Author(s):  
Fumie Nakashima ◽  
Takahiro Shibata ◽  
Koji Uchida
Keyword(s):  
Reaction Mechanism ◽  
Regulatory Mechanism ◽  
Protein S ◽  
Oxidative Modification ◽  
Cysteine Residues ◽  
Chain Reaction ◽  
Serum Albumins ◽  
Sulphydryl Group ◽  
A Chain ◽  
Unique Mechanism

Abstract Protein S-thiolation is a reversible oxidative modification that serves as an oxidative regulatory mechanism for certain enzymes and binding proteins with reactive cysteine residues. It is generally believed that the thiolation occurs at free sulphydryl group of cysteine residues. Meanwhile, despite the fact that disulphide linkages, serving structural and energetic roles in proteins, are stable and inert to oxidative modification, a recent study shows that the thiolation could also occur at protein disulphide linkages when human serum albumin (HSA) was treated with disulphide molecules, such as cystine and homocystine. A chain reaction mechanism has been proposed for the thiolation at disulphide linkages, in which free cysteine (Cys34) is involved in the reaction with disulphide molecules to form free thiols (cysteine or homocysteine) that further react with protein disulphide linkages to form the thiolated cysteine residues in the protein. This review focuses on the recent finding of this unique chain reaction mechanism of protein thiolation.

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