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Title: Models of Superoxide Dismutases

Abstract

In this review we have focused much of our discussion on the mechanistic details of how the native enzymes function and how mechanistic developments/insights with synthetic small molecule complexes possessing SOD activity have influenced our understanding of the electron transfer processes involved with the natural enzymes. A few overriding themes have emerged. Clearly, the SOD enzymes operate at near diffusion controlled rates and to achieve such catalytic turnover activity, several important physical principles must be operative. Such fast electron transfer processes requires a role for protons; i.e., proton-coupled electron transfer (''H-atom transfer'') solves the dilemma of charge separation developing in the transition state for the electron transfer step. Additionally, outer-sphere electron transfer is likely a most important pathway for manganese and iron dismutases. This situation arises because the ligand exchange rates on these two ions in water never exceed {approx}10{sup +7} s{sup -1}; consequently, 10{sup +9} catalytic rates require more subtle mechanistic insights. In contrast, copper complexes can achieve diffusion controlled (>10{sup +9}) exchange rates in water; thus inner-sphere electron transfer processes are more likely to be operative in the Cu/Zn enzymes. Recent studies have continued to expand our understanding of the mechanism of action of this most important classmore » of redox active enzymes, the superoxide dismutases, which have been critical in the successful adaptation of life on this planet to an oxygen-based metabolism. The design of SOD mimic drugs, synthetic models compounds that incorporate this superoxide dismutase catalytic activity and are capable of functioning in vivo, offers clear potential benefits in the control of diseases, ranging from the control of neurodegenerative conditions, such as Parkinson's or Alzheimer's disease, to cancer.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Energy Research (ER) (US)
OSTI Identifier:
770697
Report Number(s):
BNL-65540
TRN: US0500123
DOE Contract Number:  
AC02-98CH10886
Resource Type:
Book
Resource Relation:
Other Information: PBD: 20 May 1998
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; COPPER COMPLEXES; DIFFUSION; DISEASES; ELECTRON TRANSFER; ENZYMES; FOREIGN EXCHANGE RATE; IN VIVO; ION EXCHANGE; IRON; LIGANDS; MANGANESE; METABOLISM; NEOPLASMS; PROTONS; SUPEROXIDE DISMUTASE

Citation Formats

Cabelli, Diane E, Riley, Dennis, Rodriguez, Jorge A, Valentine, Joan Selverstone, and Zhu, Haining. Models of Superoxide Dismutases. United States: N. p., 1998. Web.
Cabelli, Diane E, Riley, Dennis, Rodriguez, Jorge A, Valentine, Joan Selverstone, & Zhu, Haining. Models of Superoxide Dismutases. United States.
Cabelli, Diane E, Riley, Dennis, Rodriguez, Jorge A, Valentine, Joan Selverstone, and Zhu, Haining. 1998. "Models of Superoxide Dismutases". United States. https://www.osti.gov/servlets/purl/770697.
@article{osti_770697,
title = {Models of Superoxide Dismutases},
author = {Cabelli, Diane E and Riley, Dennis and Rodriguez, Jorge A and Valentine, Joan Selverstone and Zhu, Haining},
abstractNote = {In this review we have focused much of our discussion on the mechanistic details of how the native enzymes function and how mechanistic developments/insights with synthetic small molecule complexes possessing SOD activity have influenced our understanding of the electron transfer processes involved with the natural enzymes. A few overriding themes have emerged. Clearly, the SOD enzymes operate at near diffusion controlled rates and to achieve such catalytic turnover activity, several important physical principles must be operative. Such fast electron transfer processes requires a role for protons; i.e., proton-coupled electron transfer (''H-atom transfer'') solves the dilemma of charge separation developing in the transition state for the electron transfer step. Additionally, outer-sphere electron transfer is likely a most important pathway for manganese and iron dismutases. This situation arises because the ligand exchange rates on these two ions in water never exceed {approx}10{sup +7} s{sup -1}; consequently, 10{sup +9} catalytic rates require more subtle mechanistic insights. In contrast, copper complexes can achieve diffusion controlled (>10{sup +9}) exchange rates in water; thus inner-sphere electron transfer processes are more likely to be operative in the Cu/Zn enzymes. Recent studies have continued to expand our understanding of the mechanism of action of this most important class of redox active enzymes, the superoxide dismutases, which have been critical in the successful adaptation of life on this planet to an oxygen-based metabolism. The design of SOD mimic drugs, synthetic models compounds that incorporate this superoxide dismutase catalytic activity and are capable of functioning in vivo, offers clear potential benefits in the control of diseases, ranging from the control of neurodegenerative conditions, such as Parkinson's or Alzheimer's disease, to cancer.},
doi = {},
url = {https://www.osti.gov/biblio/770697}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed May 20 00:00:00 EDT 1998},
month = {Wed May 20 00:00:00 EDT 1998}
}

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