The nitroxide TEMPO is an efficient scavenger of protein radicals: cellular and kinetic studies
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The nitroxide TEMPO is an efficient scavenger of protein radicals : cellular and kinetic studies. / Pattison, David I; Lam, Magdalena; Shinde, Sujata S; Anderson, Robert F; Davies, Michael Jonathan.
In: Free Radical Biology & Medicine, Vol. 53, No. 9, 01.11.2012, p. 1664-74.Research output: Contribution to journal › Journal article › peer-review
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TY - JOUR
T1 - The nitroxide TEMPO is an efficient scavenger of protein radicals
T2 - cellular and kinetic studies
AU - Pattison, David I
AU - Lam, Magdalena
AU - Shinde, Sujata S
AU - Anderson, Robert F
AU - Davies, Michael Jonathan
N1 - Copyright © 2012 Elsevier Inc. All rights reserved.
PY - 2012/11/1
Y1 - 2012/11/1
N2 - Protein oxidation occurs during multiple human pathologies, and protein radicals are known to induce damage to other cell components. Such damage may be modulated by agents that scavenge protein radicals. In this study, the potential protective reactions of the nitroxide TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl radical) against Tyr- and Trp-derived radicals (TyrO./TrpN.) have been investigated. Pretreatment of macrophage cells with TEMPO provided protection against photo-oxidation-induced loss of cell viability and Tyr oxidation, with the nitroxide more effective than the hydroxylamine or parent amine. Pulse radiolysis was employed to determine rate constants, k, for the reaction of TEMPO with TyrO. and TrpN. generated on N-Ac-Tyr-amide and N-Ac-Trp-amide, with values of k~10(8) and 7×10(6)M(-1)s(-1), respectively, determined. Analogous studies with lysozyme, chymotrypsin, and pepsin yielded k for TEMPO reacting with TrpN. ranging from 1.5×10(7) (lysozyme) to 1.1×10(8) (pepsin)M(-1)s(-1). Pepsin-derived TyrO. reacted with TEMPO with k~4×10(7)M(-1)s(-1); analogous reactions for lysozyme and chymotrypsin TyrO. were much slower. These data indicate that TEMPO can inhibit secondary reactions of both TyrO. and TrpN., though this is protein dependent. Such protein radical scavenging may contribute to the positive biological effects of nitroxides.
AB - Protein oxidation occurs during multiple human pathologies, and protein radicals are known to induce damage to other cell components. Such damage may be modulated by agents that scavenge protein radicals. In this study, the potential protective reactions of the nitroxide TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxyl radical) against Tyr- and Trp-derived radicals (TyrO./TrpN.) have been investigated. Pretreatment of macrophage cells with TEMPO provided protection against photo-oxidation-induced loss of cell viability and Tyr oxidation, with the nitroxide more effective than the hydroxylamine or parent amine. Pulse radiolysis was employed to determine rate constants, k, for the reaction of TEMPO with TyrO. and TrpN. generated on N-Ac-Tyr-amide and N-Ac-Trp-amide, with values of k~10(8) and 7×10(6)M(-1)s(-1), respectively, determined. Analogous studies with lysozyme, chymotrypsin, and pepsin yielded k for TEMPO reacting with TrpN. ranging from 1.5×10(7) (lysozyme) to 1.1×10(8) (pepsin)M(-1)s(-1). Pepsin-derived TyrO. reacted with TEMPO with k~4×10(7)M(-1)s(-1); analogous reactions for lysozyme and chymotrypsin TyrO. were much slower. These data indicate that TEMPO can inhibit secondary reactions of both TyrO. and TrpN., though this is protein dependent. Such protein radical scavenging may contribute to the positive biological effects of nitroxides.
KW - Animals
KW - Azides
KW - Cell Line
KW - Cell Survival
KW - Chymotrypsin
KW - Cyclic N-Oxides
KW - Electron Spin Resonance Spectroscopy
KW - Free Radical Scavengers
KW - Free Radicals
KW - Hydroxylamine
KW - Kinetics
KW - Macrophages
KW - Mice
KW - Muramidase
KW - Nitrogen Oxides
KW - Oxidants, Photochemical
KW - Oxidation-Reduction
KW - Pepsin A
KW - Pulse Radiolysis
KW - Tryptophan
KW - Tyrosine
U2 - 10.1016/j.freeradbiomed.2012.08.578
DO - 10.1016/j.freeradbiomed.2012.08.578
M3 - Journal article
C2 - 22974763
VL - 53
SP - 1664
EP - 1674
JO - Free Radical Biology & Medicine
JF - Free Radical Biology & Medicine
SN - 0891-5849
IS - 9
ER -
ID: 128974866