| Autor: |
Oksoo Han, Randeep Rakwal, Seung-Wook Chi, Thavrak Huon, Ilchul Kim, Je Chang Woo, Kyoungwon Cho, Sungkuk Jang |
| Rok vydání: |
2009 |
| Předmět: |
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| Zdroj: |
Bulletin of the Korean Chemical Society. 30:917-923 |
| ISSN: |
0253-2964 |
| DOI: |
10.5012/bkcs.2009.30.4.917 |
| Popis: |
The maize lipoxgyenase-1 is a non-traditional dual positional specific enzyme and the reaction proceeds via enzyme-initiated catalysis. Bioinformatic analysis indicated that the maize lipoxygenase-1 is structurally more similar to soybean LOX1 than pea LOXN2 in that it has an additional external loop (residues 318-351) in the carboxy-terminal catalytic domain. We analyzed the dependence of product distribution on concentration of linoleic acid and monitored the formation of hydroperoxyoctadecadienoic acid as a function of enzyme concentration. Product distribution was strongly influenced by substrate concentration, such that kinetically-controlled regioisomers were enriched and thermodynamically-controlled regioisomers were depleted at high substrate concentration. Kinetic studies indicated that the formation of hydroperoxyoctadecadienoic acid saturated rapidly in an enzyme concentration-dependent manner, which implied that reactivation by reoxidation of inactive Fe(II) failed to occur. Our results support the previously proposed enzyme-initiated catalytic mechanism of the maize lipoxgyenase-1 and reveals that a substrate molecule serves as a hydrogen atom donor in its enzyme-initiated catalysis. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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