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Titolo:
Enzyme-catalyzed and enzyme-triggered pathways in dioxygenation of 1-monolinoleoyl-rac-glycerol by potato tuber lipoxygenase
Autore:
Butovich, IA; Reddy, CC;
Indirizzi:
Penn State Univ, Ctr Mol Toxicol, Environm Resources Res Inst, University Pk, PA 16802 USA Penn State Univ University Pk PA USA 16802 t, University Pk, PA 16802 USA Penn State Univ, Dept Vet Sci, University Pk, PA 16802 USA Penn State Univ University Pk PA USA 16802 i, University Pk, PA 16802 USA
Titolo Testata:
BIOCHIMICA ET BIOPHYSICA ACTA-PROTEIN STRUCTURE AND MOLECULAR ENZYMOLOGY
fascicolo: 2, volume: 1546, anno: 2001,
pagine: 379 - 398
SICI:
0167-4838(20010407)1546:2<379:EAEPID>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
LINOLEIC-ACID OXIDATION; PERFORMANCE LIQUID-CHROMATOGRAPHY; DRUG-DELIVERY SYSTEMS; FUSARIUM-PROLIFERATUM; PARTIAL-PURIFICATION; ARACHIDONIC-ACID; FATTY-ACIDS; 5-LIPOXYGENASE; HYDROPEROXIDES; SPECIFICITY;
Keywords:
lipoxygenase; 1-monolinoleoyl-rac-glycerol; oxidation; cis,trans isomerization; free radical; free radical scavenger;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
60
Recensione:
Indirizzi per estratti:
Indirizzo: Butovich, IA Penn State Univ, Ctr Mol Toxicol, Environm Resources Res Inst, 115 HenningBldg, University Pk, PA 16802 USA Penn State Univ 115 Henning Bldg University Pk PA USA 16802 A
Citazione:
I.A. Butovich e C.C. Reddy, "Enzyme-catalyzed and enzyme-triggered pathways in dioxygenation of 1-monolinoleoyl-rac-glycerol by potato tuber lipoxygenase", BBA-PROT ST, 1546(2), 2001, pp. 379-398

Abstract

It was shown for the first time that potato tuber lipoxygenase (ptLOX) catalyzed the aerobic oxidation of l-monolinoleoyl-rac-glycerol (mLG) in a mixed micellar reaction solution with the non-ionic detergent monododecyl ether of decaoxyethylene glycol. No hydrolysis of mLG occurred during the reaction. The four major reaction products obtained at 23 degreesC were identified as 1-[9-hydroperoxy-10E, 12Z-octadecadienoyl]-rac-glycerol (9-(E,Z)HPODE-GE, 41%), 1-[13-hydroperoxy-9Z,11E-octadecadienoyl]-rac-glycerol (13-(Z,E3-HPODE-GE, 17%), and their all-trans isomers (similar to 21% each). The molar fraction of all-trans isomers depended on the temperature of the reaction solution; it was found that at 0 degreesC their molar fractions were similar to 15.5% each, while 9-(E,Z)HPODE-GE and 13-(Z,E)-HPODE-GE gave 42% and27%, respectively, of the overall product. A free radical scavenger, 4-hydroxy-TEMPO, dramatically increased the molar fraction of 9-(E,Z)HPODEGE, yielding 83% at 23 degreesC, at the expense of all other products. Chiral HPLC of 9-(E,Z)HPODE-GE formed in the presence of 4-hydroxy-TEMPO revealed that it was composed of similar to 94% S and similar to6% (R) isomers. This assures largely a uniform orientation of mLG molecules in the ptLOX active center, with their methyl end most likely deepened into the protein globule, The second major product, 13-(Z,E)-HPODE-GE, which yielded similar to9% of the total product formed in the presence of 4-hydroxy-TEMPO, was racemic, and so were the all-trans isomers. Therefore, the last three cannot be considered the true products of the enzyme reaction, which is known to be stereospecific. It appears that they were formed as a result of (i) leakage of the pentadienyl radicals from the ptLOX active center and their subsequent non-enzymatic dioxygenation, and/ or (ii) leakage of the peroxyl radicals leading to a free radical chain reaction affording all positional, geometricaland stereoisomers of the products. This reaction resembles ptLOX oxidationof another non-ionizable substrate, linoleyl alcohol [I.A. Butovich, S.M. Luk'yanova, C.C. Reddy, Arch. Biochem. Biophys. 378 (2000) 65-77], and differed substantially from oxidation of ionizable linoleic acid. Consequently,formation of large amounts of the non-specific oxidation products might beconsidered a universal characteristic of ptLOX oxidation of non-ionizable compounds. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 09:46:48