TY - JOUR
T1 - Formation of a protein-bound pyrazinium free radical cation during glycation of histone H1
AU - Wondrak, Georg T.
AU - Varadarajan, Sridhar
AU - Butterfield, D. Allan
AU - Jacobson, Myron K.
N1 - Funding Information:
This research was supported by National Institutes of Health Grants CA43894 and NS38496.
PY - 2000/9/15
Y1 - 2000/9/15
N2 - Glycation, the nonenzymatic reaction between protein amino groups and reducing sugars, induces protein damage that has been linked to several pathological conditions, especially diabetes, and general aging. Here we describe the direct identification of a protein-bound free radical formed during early glycation of histone H1 in vitro. Earlier EPR analysis of thermal browning reactions between free amino acids and reducing sugars has implicated the sugar fragmentation product glycolaldehyde in the generation of a 1,4-disubstituted pyrazinium free radical cation. In order to evaluate the potential formation of this radical in vivo, the early glycation of BSA, lysozyme, and histone H1 by several sugars (D-glucose, D-ribose, ADP-ribose, glycolaldehyde) under conditions of physiological pH and temperature was examined by EPR. The pyrazinium free radical cation was identified on histone H1 glycated by glycolaldehyde (g = 2.00539, a(N) = 8.01 [2N], a(H) = 5.26 [4H], a(H) = 2.72 [4H]), or ADP-ribose. Reaction of glycolaldehyde with poly- L-lysine produced an identical signal, whereas reaction with BSA or lysozyme produced only a minor unresolved singlet signal. In the absence of oxygen the signal was stable over several days. Our results raise the possibility that pyrazinium radicals may form during glycation of histone H1 in vivo. (C) 2000 Elsevier Science Inc.
AB - Glycation, the nonenzymatic reaction between protein amino groups and reducing sugars, induces protein damage that has been linked to several pathological conditions, especially diabetes, and general aging. Here we describe the direct identification of a protein-bound free radical formed during early glycation of histone H1 in vitro. Earlier EPR analysis of thermal browning reactions between free amino acids and reducing sugars has implicated the sugar fragmentation product glycolaldehyde in the generation of a 1,4-disubstituted pyrazinium free radical cation. In order to evaluate the potential formation of this radical in vivo, the early glycation of BSA, lysozyme, and histone H1 by several sugars (D-glucose, D-ribose, ADP-ribose, glycolaldehyde) under conditions of physiological pH and temperature was examined by EPR. The pyrazinium free radical cation was identified on histone H1 glycated by glycolaldehyde (g = 2.00539, a(N) = 8.01 [2N], a(H) = 5.26 [4H], a(H) = 2.72 [4H]), or ADP-ribose. Reaction of glycolaldehyde with poly- L-lysine produced an identical signal, whereas reaction with BSA or lysozyme produced only a minor unresolved singlet signal. In the absence of oxygen the signal was stable over several days. Our results raise the possibility that pyrazinium radicals may form during glycation of histone H1 in vivo. (C) 2000 Elsevier Science Inc.
KW - ADP-ribose
KW - Electron paramagnetic resonance
KW - Free radicals
KW - Glutathione
KW - Glycation
KW - Glycolaldehyde
KW - Histone H1
KW - Pyrazinium free radical
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U2 - 10.1016/S0891-5849(00)00406-8
DO - 10.1016/S0891-5849(00)00406-8
M3 - Article
C2 - 11025199
AN - SCOPUS:0034665331
VL - 29
SP - 557
EP - 567
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
SN - 0891-5849
IS - 6
ER -