Size matters: The catalytic mechanism of onoceroid synthase (bifunctional C₃₀/C₃₅ terpene cyclase) is analyzed for the first time by using mutant enzymes. The mutant enzyme Y167A produces tricyclic triterpene from C₃₀ squalene. The bulk size at the Y167 position is significant for termination of the cyclization of squalene at the bicyclic step.

中文翻译：

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双功能三萜/七萜烯环化酶的催化机理分析：Tyr167在双环步骤终止角鲨烯环化的功能

大小问题：使用突变酶首次分析了类癌合酶（双功能C ₃₀ / C ₃₅萜烯环化酶）的催化机理。突变酶Y167A从C ₃₀角鲨烯生产三环三萜。在Y167位置的体积对于在双环步骤终止角鲨烯的环化是重要的。