| 摘要 |
A cell free extract from a ciliate microorganism, including protozoo Tetrahymena, wherein the extract comprises a homogenate a microsomal fraction, a desaturaseenriched fraction or a mixture thereof and, more particularly the invention provides substantially pure enzymes: DELTA 7 cholesterol desaturases and DELTA 22 cholesterol desaturase enzymes. <??>The present invention provides methods for decreasing the cholesterol content of a foodstuff of animal origin, such as a dairy product. The methods comprise the step of treating a foodstuff by incubating the same with a cell free extract in a effective amount to enable changes in the foodstuff: (a)reduce the level of cholesterol; and (b) increase the level of at least one desaturated cholesterol derivative: DELTA 7- dehydrocholesterol, DELTA 22 dehydrocholesterol and/or DELTA 7,22 bisdehydrocholesterol. <??>The invention also relates to methods for recovering cholesterol desaturases activities from ciliates, including Tetrahymena, and their use in a production of DELTA 7 dehydrosterol, DELTA 22 dehydrosterol and DELTA 7,22 bis dehydrosterol from several sterol sources as cholesterol. |
