Kreuz K, Kleinig H
Eur J Biochem. 1984 Jun 15;141(3):531-5. doi: 10.1111/j.1432-1033.1984.tb08225.x.
Purified spinach chloroplasts incorporate [1-14C]isopentenyl diphosphate into prenyl lipids in high yields. The immediate biosynthetic precursors of isopentenyl diphosphate (hydroxymethylglutaryl-CoA, mevalonate, mevalonate-5-phosphate, mevalonate-5-diphosphate), on the other hand, are not accepted as substrates and the corresponding enzymes hydroxymethylglutaryl-CoA reductase, mevalonate kinase, phosphomevalonate kinase, and diphosphomevalonate decarboxylase are not present in the organelles. These enzymes can only be detected in a membrane-bound form at the endoplasmic reticulum (hydroxymethylglutaryl-CoA reductase) and as soluble activities in the cytoplasm. The concept is developed that isopentenyl diphosphate is formed in the cytoplasm as a 'central intermediate' and is distributed then to other cellular compartments (endoplasmic reticulum, plastids, mitochondria) for further biosynthetic utilization.
纯化的菠菜叶绿体能够高效地将[1-14C]异戊烯基二磷酸掺入类异戊二烯脂质中。另一方面，异戊烯基二磷酸的直接生物合成前体（羟甲基戊二酰辅酶A、甲羟戊酸、甲羟戊酸-5-磷酸、甲羟戊酸-5-二磷酸）不被接受作为底物，并且相应的酶羟甲基戊二酰辅酶A还原酶、甲羟戊酸激酶、磷酸甲羟戊酸激酶和二磷酸甲羟戊酸脱羧酶在细胞器中不存在。这些酶只能在内质网以膜结合形式（羟甲基戊二酰辅酶A还原酶）以及在细胞质中以可溶性活性形式被检测到。由此提出了一个概念，即异戊烯基二磷酸在细胞质中作为“中心中间体”形成，然后分布到其他细胞区室（内质网、质体、线粒体）进行进一步的生物合成利用。
