title: Expression of a Streptomyces 3-hydroxysteroid oxidase gene in oilseeds for converting phytosterols to phytostanols.
abstract: Plant sterols and their hydrogenated forms, stanols, have attracted much attention because of their benefits to human health in reducing serum and LDL cholesterol levels, with vegetable oil processing being their major source in several food products currently sold. The predominant forms of plant sterol end products are sitosterol, stigmasterol, campesterol and brassicasterol (in brassica). In this study, 3-hydroxysteroid oxidase from Streptomyces hygroscopicus was utilized to engineer oilseeds from rapeseed (Brassica napus) and soybean (Glycine max), respectively, to modify the relative amounts of specific sterols to stanols. Each of the major phytosterols had its C-5 double bond selectively reduced to the corresponding phytostanol without affecting other functionalities, such as the C-22 double bond of stigmasterol in soybean seed and of brassicasterol in rapeseed. Additionally, several novel phytostanols were obtained that are not produced by chemical hydrogenation of phytosterols normally present in plants.
authors.affiliation: Agriculture Biotechnology, Monsanto Company, 800 N. Lindbergh Boulevard, St. Louis, MO 63167, USA.
authors.forename: Mylavarapu
authors.initials: M
authors.lastname: Venkatramesh
authors.forename: Balasulojini
authors.initials: B
authors.lastname: Karunanandaa
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.forename: Catharine A
authors.initials: CA
authors.lastname: Gunter
authors.forename: Sekhar
authors.initials: S
authors.lastname: Boddupalli
authors.forename: Ganesh M
authors.initials: GM
authors.lastname: Kishore
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics* / Q000378:metabolism*; D029688:Brassica napus / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D005798:Genes, Bacterial / Q000235:genetics; D005818:Genetic Engineering; D006865:Hydrogenation; D015394:Molecular Structure; D010840:Phytosterols / Q000378:metabolism*; D030821:Plants, Genetically Modified; D012639:Seeds / Q000235:genetics / Q000378:metabolism*; D013025:Glycine max / Q000235:genetics / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics
chemical_list: D010840:Phytosterols; D015096:3-Hydroxysteroid Dehydrogenases