کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
21725 | 43237 | 2008 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Characterization of novel cholesterol esterase from Trichoderma sp. AS59 with high ability to synthesize steryl esters Characterization of novel cholesterol esterase from Trichoderma sp. AS59 with high ability to synthesize steryl esters](/preview/png/21725.png)
A novel cholesterol esterase with there and throughout to synthesisze steryl ester was obtained from the culture filtrate of a fungal strain Trichoderma sp. AS59 isolated from soil. The extracellular enzyme was a monomeric protein with a molecular mass of approximately 58 kDa and an isoelectric point of 4.3. The optimal temperature was between 35°C and 40°C, and the optimal pH was 7.0. The enzyme retained 75% of the initial activity after 18 h of incubation at 30°C in the pH range of 3.5–7.5. Its relative hydrolytic activities on fatty acid cholesteryl esters were in the following order: butyrate (121%), linoleate (100%), caprylate (79%), myristate (42%), palmitate (38%), caproate (37%), and laurate (35%). Unlike mammalian pancreatic cholesterol esterase that is activated by primary cholates on hydrolysis of long-chain fatty acid cholesteryl esters, the enzyme from Trichoderma sp. AS59 displayed its basal activity and was not affected by cholate up to a concentration of 5 mM. At higher cholate concentrations the activity gradually decreased, but reincreased at about 40 mM to reach more than twice the basal activity at 100 mM. The enzyme exhibited a broad substrate specificity, being capable of hydrolyzing various fatty acid esters of not only cholesterol, but also methanol, glycerol, and p-nitrophenol. When incubated with a mixture of cholesterol and oleic acid of equal amounts, the enzyme achieved stoichiometrical esterification in 5 h, indicating its potential utility in food additives and liquid crystal devices.
Journal: Journal of Bioscience and Bioengineering - Volume 105, Issue 4, April 2008, Pages 341–349