萜类骨架生物合成
中文名称
通路描述
萜类（也称为异戊二烯）是一类天然产物，由异戊二烯（C5）单元组成。存在两种生物合成途径，即甲戊途径 [MD:M00095] 和非甲戊途径或 MEP/DOXP 途径 [MD:M00096]，用于构建萜类前体：异戊烯二磷酸（IPP）和二甲基烯丙基二磷酸（DMAPP）。前萜化酶的作用则产生高级前体：异戊二烯二磷酸（GPP）、芳基二磷酸（FPP）和异戊二烯二磷酸（GGPP），它们分别是单萜类（C10）、倍半萜类（C15）和二萜类（C20）的前体。这些前体的缩合产生类固醇（C30）和胡萝卜素（C40）的前体。MEP/DOXP 途径在高等动物和真菌中不存在，但在绿色植物中，MEP/DOXP 和甲戊途径在细胞的不同细胞器中共同存在。在叶绿体中运行的 MEP/DOXP 途径负责形成必需油单萜类、香茅醛、一些倍半萜类、二萜类和胡萝卜素以及植物醇（Phytol）。甲戊途径在细胞质中运行，产生三萜类、类固醇和大多数倍半萜类。
英文描述
Terpenoids, also known as isoprenoids, are a large class of natural products consisting of isoprene (C5) units. There are two biosynthetic pathways, the mevalonate pathway [MD:M00095] and the non-mevalonate pathway or the MEP/DOXP pathway [MD:M00096], for the terpenoid building blocks: isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). The action of prenyltransferases then generates higher-order building blocks: geranyl diphosphate (GPP), farsenyl diphosphate (FPP), and geranylgeranyl diphosphate (GGPP), which are the precursors of monoterpenoids (C10), sesquiterpenoids (C15), and diterpenoids (C20), respectively. Condensation of these building blocks gives rise to the precursors of sterols (C30) and carotenoids (C40). The MEP/DOXP pathway is absent in higher animals and fungi, but in green plants the MEP/DOXP and mevalonate pathways co-exist in separate cellular compartments. The MEP/DOXP pathway, operating in the plastids, is responsible for the formation of essential oil monoterpenes and linalyl acetate, some sesquiterpenes, diterpenes, and carotenoids and phytol. The mevalonate pathway, operating in the cytosol, gives rise to triterpenes, sterols, and most sesquiterpenes.
所含基因
23 个基因