Kinetic Properties of Lipoxygenase from Desert Truffle (Terfezia claveryi Chatin) Ascocarps: Effect of Inhibitors and Activators
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- 作者：Manuela Pé ; rez-Gilabert ; Isabel Sá ; nchez-Felipe ; Asunció ; n Morte ; and Francisco Garcí ; a-Carmona
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：July 27, 2005
- 年：2005
- 卷：53
- 期：15
- 页码：6140 - 6145
- 全文大小：112K
- 年卷期：v.53,no.15(July 27, 2005)
- ISSN：1520-5118
文摘
There is very little information available on the kinetic characteristics of fungal lipoxygenases (LOXs)because most data on the mechanism of this enzyme concern soybean LOX. In this paper, the kineticproperties of LOX from Terfezia claveryi Chatin ascocarps were studied for the first time. The enzymedid not show the "substrate aggregation-dependent activity" described for other LOXs and presenteda Km for linoleic acid of 41 
M at pH 7.0. The effect of different inhibitors was also studied. Theenzyme presented the characteristic lag phase of other LOXs, and the influence of different factorson its duration was analyzed. The lag period was reduced not only by the product of the reaction(13-HPOD) but also by 9-HPOD. Calculation of the activation constant is proposed for the first timeas a useful tool for the characterization of LOX because this method makes it possible to quantifythe effectiveness of different hydroperoxides as LOX activators. The activation constants obtainedwere 0.3 and 6.4 M for 13- and 9-HPOD, respectively; thus, the product of the reaction was ~21-fold more effective than 9-HPOD as a T. claveryi LOX activator.Keywords: Activation constant; ascocarp; desert truffle; hydroperoxide; kinetic mechanism; fungus;inhibitor; lag period; lipoxygenase; Terfezia; Triton X-114.
M at pH 7.0. The effect of different inhibitors was also studied. Theenzyme presented the characteristic lag phase of other LOXs, and the influence of different factorson its duration was analyzed. The lag period was reduced not only by the product of the reaction(13-HPOD) but also by 9-HPOD. Calculation of the activation constant is proposed for the first timeas a useful tool for the characterization of LOX because this method makes it possible to quantifythe effectiveness of different hydroperoxides as LOX activators. The activation constants obtainedwere 0.3 and 6.4 M for 13- and 9-HPOD, respectively; thus, the product of the reaction was ~21-fold more effective than 9-HPOD as a T. claveryi LOX activator.Keywords: Activation constant; ascocarp; desert truffle; hydroperoxide; kinetic mechanism; fungus;inhibitor; lag period; lipoxygenase; Terfezia; Triton X-114.