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Epoxyalcohol Synthase RjEAS (CYP74A88) from the Japanese Buttercup (Ranunculus japonicus): Cloning and Characterization of Catalytic Properties

Y. Y. Toporkova1,a*, V. S. Fatykhova1, S. S. Gorina1, L. S. Mukhtarova1, and A. N. Grechkin1

1Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center of Russian Academy of Sciences, 420111 Kazan, Tatarstan, Russia

* To whom correspondence should be addressed.

Received April 13, 2018; Revised October 7, 2018; Accepted October 7, 2018
Cytochromes P450 of the CYP74 family play a key role in the lipoxygenase cascade generating oxylipins (products of polyunsaturated fatty acid oxidation). The CYP74 family includes allene oxide synthases, hydroperoxide lyases, divinyl ether synthases, and epoxyalcohol synthases. In this work, we cloned the CYP74A88 gene from the Japanese buttercup (Ranunculus japonicus) and studied the properties of the encoded recombinant protein. The CYP74A88 enzyme specifically converts linoleic acid 9- and 13-hydroperoxides to oxiranyl carbinols 9,10-epoxy-11-hydroxy-12-octadecenoic acid and 11-hydroxy-12,13-epoxy-9-octadecenoic acid, respectively, which was confirmed by GC-MS analysis and kinetic studies. Therefore, the CYP74A88 enzyme is a specific epoxyalcohol synthase.
KEY WORDS: lipoxygenase cascade, cytochromes P450, CYP74 family, epoxyalcohol synthase, Ranunculus japonicus

DOI: 10.1134/S0006297919020081