OXIDATION MECHANISM OF VITAMIN-E ANALOG (TROLOX-C, 6-HYDROXY-2,2,5,7,8-PENTAMETHYLCHROMAN) AND VITAMIN-E BY HORSERADISH-PEROXIDASE AND MYOGLOBIN

被引:36
作者
NAKAMURA, M [1 ]
HAYASHI, T [1 ]
机构
[1] HOKKAIDO INST PUBL HLTH, KITA KU, SAPPORO, JAPAN
关键词
D O I
10.1016/0003-9861(92)90280-A
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The oxidation of 6-hydroxy-2,2,5,7,8-pentamethylchroman, Trolox C, and α-tocopherol by horseradish peroxidase was examined by stopped- flow and ESR experiments. The catalytic intermediate of horseradish peroxidase during the oxidation of vitamin E analogues and vitamin E was invariably Compound II, and rate constants for the rate-determining step decreased in the order 6-hydroxy-2,2,5,7,8-pentamethylchroman > Trolox C > α-tocopherol. The formation of phenoxyl radicals from substrates was verified with ESR and was followed optically. Resulting 6-hydroxy-2,2,5,7,8-pentamethylchroman and Trolox C radicals decayed through a dismutation reaction, followed by formation of the quinoid form via a transient intermediate. The sequence of events after formation of 6-hydroxy-2,2,5,7,8-pentamethylchroman and Trolox C radicals was similar to that observed by pulse radiolysis (Thomas M. J. and Bielski, B. H. J. (1989). J. Am. Chem. Soc. 111, 3315-3319). Final oxidation products of 6-hydroxy-2,2,5,7,8-pentamethylchroman and Trolox C were identified as the quinoid forms and were obtained quantitatively whether or not the analogue had a carboxyl or methyl group at the 2-position of chroman ring. In contrast, enzymatic oxidation of a-tocopherol gave α-tocopherol quinone in very low yield. Conversion of 6-hydroxy-2,2,5,7,8-pentamethylchroman, Trolox C, and α-tocopherol to the corresponding quinones was also catalyzed by metmyoglobin in a reaction completely inhibited by ascorbate. © 1992.
引用
收藏
页码:313 / 319
页数:7
相关论文
共 46 条
[1]   ASCORBIC ACID FREE RADICALS .1. PULSE RADIOLYSIS STUDY OF OPTICAL ABSORPTION AND KINETIC PROPERTIES [J].
BIELSKI, BHJ ;
COMSTOCK, DA ;
BOWEN, RA .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1971, 93 (22) :5624-&
[2]   ON THE OCCURRENCE OF ALPHA-TOCOPHEROLQUINONE IN RAT-TISSUE [J].
BIERI, JG ;
TOLLIVER, TJ .
LIPIDS, 1981, 16 (10) :777-779
[3]   REPAIR OF AMINO-ACID RADICALS BY A VITAMIN-E ANALOG [J].
BISBY, RH ;
AHMED, S ;
CUNDALL, RB .
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 1984, 119 (01) :245-251
[4]  
BURTON GW, 1986, ACCOUNTS CHEM RES, V19, P194, DOI 10.1021/ar00127a001
[5]   AUTOXIDATION OF BIOLOGICAL MOLECULES .1. THE ANTIOXIDANT ACTIVITY OF VITAMIN-E AND RELATED CHAIN-BREAKING PHENOLIC ANTIOXIDANTS INVITRO [J].
BURTON, GW ;
INGOLD, KU .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1981, 103 (21) :6472-6477
[6]  
CHAMULITRAT W, 1989, J BIOL CHEM, V264, P20968
[7]   METABOLISM OF C14-ALPHA-TOCOPHERYL QUINONE AND C-14-ALPHA-TOCOPHERYL HYDROQUINONE [J].
CHOW, CK ;
DRAPER, HH ;
CSALLANY, AS ;
CHIU, M .
LIPIDS, 1967, 2 (05) :390-&
[8]  
DAVIES MJ, 1988, BIOCHEM J, V255, P513
[9]   OXIDATION OF ALPHA-TOCOPHEROL IN MICELLES AND LIPOSOMES BY THE HYDROXYL, PERHYDROXYL, AND SUPEROXIDE FREE-RADICALS [J].
FUKUZAWA, K ;
GEBICKI, JM .
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 1983, 226 (01) :242-251
[10]   FERRYLMYOGLOBIN-CATALYZED LINOLEIC-ACID PEROXIDATION [J].
GALARIS, D ;
SEVANIAN, A ;
CADENAS, E ;
HOCHSTEIN, P .
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 1990, 281 (01) :163-169