Institut für Biologie II, Zellbiologie, Universität Freiburg, Schänzlestrasse 1, D-7800, Freiburg, Germany.
Planta. 1987 Jul;171(3):406-11. doi: 10.1007/BF00398686.
Seedlings from the white mustard, Sinapis alba, grown under continuous far-red light exhibit enhanced plastid enzyme activities when compared with dark-grown seedlings (for review, see Mohr 1981). These activities are even more pronounced upon illumination with white light during the etioplast/chloroplast transformation. Etioplasts and etiochloroplasts from the cotyledons of such seedlings show high prenyl-lipid-synthesizing activities when [1-(14)C]isopentenyl diphosphate is used as the precursor. They lack, however, any enzymatic activities for the formation of isopentenyl diphosphate via the mevalonate pathway, i.e. hydroxymethylglutaryl-CoA reductase, mevalonate kinase, phosphomevalonate kinase and diphosphomevalonate decarboxylase, which are present and easily detectable within the endoplasmic reticulum and cytoplasm. These results corroborate the view that the cytoplasm of the plant cell is the only site of isopentenyl-diphosphate formation via the mevalonate pathway.
在连续远红光下生长的白芥幼苗与黑暗中生长的幼苗相比，质体酶活性增强（综述见 Mohr 1981）。在质体/叶绿体转化过程中用白光照射时，这些活性更为明显。来自这些幼苗子叶的原质体和黄化质体在使用[1-(14)C]异戊烯二磷酸作为前体时表现出高的 prenyl-lipid-合成活性。然而，它们缺乏通过甲羟戊酸途径形成异戊烯二磷酸的任何酶活性，即羟甲基戊二酰辅酶 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，这些酶存在于内质网和细胞质中，很容易检测到。这些结果证实了细胞质是植物细胞通过甲羟戊酸途径形成异戊烯二磷酸的唯一部位的观点。
