title: Comparison of Biochemical Properties of the Original and Newly Identified Oleate Hydratases from Stenotrophomonas maltophilia.
abstract: Oleate hydratases (OhyAs) catalyze the conversion of unsaturated fatty acids to 10-hydroxy fatty acids, which are used as precursors of important industrial compounds, including lactones and ω-hydroxycarboxylic and α,ω-dicarboxylic acids. The genes encoding OhyA and a putative fatty acid hydratase inStenotrophomonas maltophiliawere identified by genomic analysis. The putative fatty acid hydratase was purified and identified as an oleate hydratase (OhyA2) based on its substrate specificity. The activity of OhyA2 as a holoenzyme was not affected by adding cofactors, whereas the activity of the original oleate hydratase (OhyA1) showed an increase. Thus, all characterized OhyAs were categorized as either OhyA1 or OhyA2 based on the activities of holoenzymes upon adding cofactors, which were determined by the type of the fourth conserved amino acid of flavin adenine dinucleotide (FAD)-binding motif. The hydration activities ofS. maltophiliaOhyA2 toward unsaturated fatty acids, including oleic acid, palmitoleic acid, linoleic acid, α-linolenic acid, and γ-linolenic acid, were greater than those of OhyA1. Moreover, the specific activity ofS. maltophiliaOhyA2 toward unsaturated fatty acids, with the exception of γ-linolenic acid, was the highest among all reported OhyAs.IMPORTANCEAll characterized OhyAs were categorized as OhyA1s or OhyA2s based on the different properties of the reported and newly identified holo-OhyAs inS. maltophiliaupon the addition of cofactors. OhyA2s showed higher activities toward polyunsaturated fatty acids (PUFAs), including linoleic acid, α-linolenic acid, and γ-linolenic acid, than those of OhyA1s. This suggests that OhyA2s can be used more effectively to convert plant oils to 10-hydroxy fatty acids because plant oils contain not only oleic acid but also PUFAs. The hydration activity of the newly identified OhyA2 fromS. maltophiliatoward oleic acid was the highest among the activity levels reported so far. Therefore, this enzyme is an efficient biocatalyst for the conversion of plant oils to 10-hydroxy fatty acids, which can be further converted to important industrial materials.
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea.
authors.forename: Woo-Ri
authors.initials: WR
authors.lastname: Kang
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea.
authors.forename: Min-Ju
authors.initials: MJ
authors.lastname: Seo
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea.
authors.forename: Kyung-Chul
authors.initials: KC
authors.lastname: Shin
authors.affiliation: Department of Food Science and Engineering, Ewha Womans University, Seoul, Republic of Korea.
authors.forename: Jin-Byung
authors.initials: JB
authors.lastname: Park
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea deokkun@konkuk.ac.kr.
authors.forename: Deok-Kun
authors.initials: DK
authors.lastname: Oh
mesh_terms: D003067:Coenzymes / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D006836:Hydro-Lyases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D019301:Oleic Acid / Q000378:metabolism*; D020615:Stenotrophomonas maltophilia / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D003067:Coenzymes; D005231:Fatty Acids, Unsaturated; D019301:Oleic Acid; D006836:Hydro-Lyases
keywords: Stenotrophomonas maltophilia; enzyme characterization; oleate hydratase