title: Synthesis of fatty acid sterol esters using cholesterol esterase from Trichoderma sp. AS59.
abstract: We recently reported the characterization of novel cholesterol esterase (EC. 3.1.1.13) from Trichoderma sp. and preliminary work on sterol ester synthesis. In the present study, we further examined the enzyme ability to synthesize cholesterol esters from cholesterol and free fatty acids of various chain lengths, and compared the fatty acid specificity in synthesis with that in hydrolysis. The enzyme catalyzed the synthesis of medium- and long-chain fatty acid cholesterol esters, but failed to synthesize short-chain fatty acid esters. The fatty acid specificities in the synthesis and hydrolysis of cholesterol esters were entirely different from each other. Unlike other lipolytic enzymes, the enzyme was largely independent of water content in the synthesis of cholesterol oleate, and it achieved near-complete esterification in the presence of an equimolar excess of oleic acid. Of additional interest is the finding that the addition of n-hexane markedly enhanced the esterification activities on all the medium- and long-chain saturated fatty acids used. Based on these findings, we attempted to synthesize stigmasterol stearate as a food additive to lower cholesterol levels in blood plasma, and found that the enzyme catalyzed effective synthesis of the ester without the need of dehydration during the reaction, indicating the potential utility of the enzyme in the food industry.
authors: Faculty of Engineering, Tokushima Bunri University, 1314-1 Shido, Sanuki 769-2193, Japan.
authors: Naoya
authors: N
authors: Morinaga
authors: Atsushi
authors: A
authors: Maeda
authors: Takayuki
authors: T
authors: Mizuno
authors: Masanori
authors: M
authors: Bunya
authors: Shigeo
authors: S
authors: Sugihara
authors: Akio
authors: A
authors: Sugihara
mesh_terms: D000924:Anticholesteremic Agents; D055162:Biocatalysis; D002784:Cholesterol / Q000378:metabolism; D002788:Cholesterol Esters / Q000096:biosynthesis*; D004951:Esterification; D005227:Fatty Acids / Q000378:metabolism*; D005232:Fatty Acids, Volatile / Q000378:metabolism; D005503:Food Additives; D019649:Food Industry / Q000379:methods; D005656:Fungal Proteins / Q000378:metabolism*; D006586:Hexanes / Q000494:pharmacology; D006868:Hydrolysis; D015394:Molecular Structure; D019301:Oleic Acid / Q000378:metabolism; D009829:Oleic Acids / Q000378:metabolism; D010840:Phytosterols / Q000378:metabolism*; D013228:Stearates / Q000138:chemical synthesis; D002787:Sterol Esterase / Q000378:metabolism*; D013265:Stigmasterol / Q000031:analogs & derivatives / Q000138:chemical synthesis; D013379:Substrate Specificity; D014242:Trichoderma / Q000201:enzymology*; D014304:Triolein / Q000378:metabolism; D014867:Water
chemical_list: D000924:Anticholesteremic Agents; D002788:Cholesterol Esters; D005227:Fatty Acids; D005232:Fatty Acids, Volatile; D005503:Food Additives; D005656:Fungal Proteins; D006586:Hexanes; D009829:Oleic Acids; D010840:Phytosterols; D013228:Stearates; D014867:Water; D014304:Triolein; C026385:n-hexane; D019301:Oleic Acid; C005576:methyl oleate; D002784:Cholesterol; D013265:Stigmasterol; D002787:Sterol Esterase