Hydrogen Tunneling in a Prokaryotic Lipoxygenase

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• 作者：Cody A. Marcus Carr ; Judith P. Klinman
• 刊名：Biochemistry
• 出版年：2014
• 出版时间：April 15, 2014
• 年：2014
• 卷：53
• 期：14
• 页码：2212-2214
• 全文大小：166K
• 年卷期：v.53,no.14(April 15, 2014)
• ISSN：1520-4995

文摘

A bacterial lipoxygenase (LOX) shows a deuterium kinetic isotope effect (KIE) that is similar in magnitude and temperature dependence to the very large KIE of eukaryotic LOXs. This occurs despite the evolutionary distance, an 25% smaller catalytic domain, and an increase in E_a of 11 kcal/mol. Site-specific mutagenesis leads to a protein variant with an E_a similar to that of the prototypic plant LOX, providing possible insight into the origin of evolutionary differences. These findings, which extend the phenomenon of hydrogen tunneling to a prokaryotic LOX, are discussed in the context of a role for protein size and/or flexibility in enzymatic hydrogen tunneling.