Hydrogen transfer in the presence of amino acid radicals

1997 ◽  
Vol 97 (1-4) ◽  
pp. 289-300 ◽  
Author(s):  
Per E. M. Siegbahn ◽  
Margareta R. A. Blomberg ◽  
Robert H. Crabtree
Keyword(s):  
Amino Acid ◽  
Hydrogen Transfer ◽  
Amino Acid Radicals

Repair of Amino Acid Radicals of Apolipoprotein B100 of Low-Density Lipoproteins by Flavonoids. A Pulse Radiolysis Study with Quercetin and Rutin†

Biochemistry ◽  
2002 ◽  
Vol 41 (36) ◽  
pp. 11057-11064 ◽  
Author(s):  
Paulo Filipe ◽  
Patrice Morlière ◽  
Larry K. Patterson ◽  
Gordon L. Hug ◽  
Jean-Claude Mazière ◽  
...  
Keyword(s):  
Amino Acid ◽  
Pulse Radiolysis ◽  
Low Density Lipoproteins ◽  
Low Density ◽  
Apolipoprotein B100 ◽  
Amino Acid Radicals

ChemInform Abstract: Nitrate Esters in the Generation of Amino Acid Radicals.

ChemInform ◽  
2010 ◽  
Vol 28 (27) ◽  
pp. no-no
Author(s):  
C. J. EASTON ◽  
A. J. IVORY ◽  
C. A. SMITH
Keyword(s):  
Amino Acid ◽  
Nitrate Esters ◽  
Amino Acid Radicals

scholarly journals Proton-coupled electron transfer: the mechanistic underpinning for radical transport and catalysis in biology

2006 ◽  
Vol 361 (1472) ◽  
pp. 1351-1364 ◽  
Author(s):  
Steven Y Reece ◽  
Justin M Hodgkiss ◽  
JoAnne Stubbe ◽  
Daniel G Nocera
Keyword(s):  
Electron Transfer ◽  
Amino Acid ◽  
Active Sites ◽  
Bond Activation ◽  
Mechanical Effect ◽  
Model Systems ◽  
Tyrosyl Radical ◽  
Quantum Mechanical Effect ◽  
Proton Coupled Electron Transfer ◽  
Amino Acid Radicals

Charge transport and catalysis in enzymes often rely on amino acid radicals as intermediates. The generation and transport of these radicals are synonymous with proton-coupled electron transfer (PCET), which intrinsically is a quantum mechanical effect as both the electron and proton tunnel. The caveat to PCET is that proton transfer (PT) is fundamentally limited to short distances relative to electron transfer (ET). This predicament is resolved in biology by the evolution of enzymes to control PT and ET coordinates on highly different length scales. In doing so, the enzyme imparts exquisite thermodynamic and kinetic controls over radical transport and radical-based catalysis at cofactor active sites. This discussion will present model systems containing orthogonal ET and PT pathways, thereby allowing the proton and electron tunnelling events to be disentangled. Against this mechanistic backdrop, PCET catalysis of oxygen–oxygen bond activation by mono-oxygenases is captured at biomimetic porphyrin redox platforms. The discussion concludes with the case study of radical-based quantum catalysis in a natural biological enzyme, class I Escherichia coli ribonucleotide reductase. Studies are presented that show the enzyme utilizes both collinear and orthogonal PCET to transport charge from an assembled diiron-tyrosyl radical cofactor to the active site over 35 Å away via an amino acid radical-hopping pathway spanning two protein subunits.

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