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Oxidosqualene cyclases (OSC) are enzymes involved in cyclization reactions of 2,3-oxidosqualene to form sterols or triterpenes. There are two major groups of sterol-producing OSC enzymes: * Cycloartenol synthase (CAS), found in all plants, which produces primarily cycloartenol * Lanosterol synthase (LAS), found in all animals and fungi, and occasionally in plants, which produces primarily lanosterol Sterols and triterpenes are extremely diverse classes of natural products, particularly in plants, which often contain numerous OSC enzymes with different substrate and product specificities;〔 common examples include lupeol synthase and beta-amyrin synthase. OSC enzymes' catalytic mechanism is similar to the prokaryotic squalene-hopene cyclase. Directed evolution and protein design have been used to identify small numbers of point mutations that alter the product specificities of OSC enzymes, most notably in altering a cycloartenol synthase to produce predominantly lanosterol. ==References== 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Oxidosqualene cyclase」の詳細全文を読む スポンサード リンク
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