Bowden L, Lord J M
Biochem J. 1976 Feb 15;154(2):491-9. doi: 10.1042/bj1540491.
Microsomal fractions, glyoxysomes and mitochondria were isolated from homogenates of germinating castor-bean (Ricinus communis) endosperm by sucrose-density-gradient centrifugation. Washed membrane preparations from these cellular fractions were examined by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. At corresponding developmental stages the endoplasmic-reticulum and glyoxysomal membranes were strikingly similar in polypeptide composition, at least 16 polypeptides being present in membranes isolated from 3-day-old tissue. Supplying [35S]methionine to intact endosperm tissue resulted in the labelling of all membrane polypeptides, the specific radioactivity in the endoplasmic reticulum being greater than for equivalent polypeptides of the glyoxysomal membrane. Washing these membranes with sodium deoxycholate solution extensively solubilized protein components, with the exception of a predominant polypeptide of mol.wt. 55000. Mitochondrial membrane preparations differed from those of the endoplasmic reticulum and glyoxysomes in polypeptide molecular-weight distribution and the [35S]methionine-labelling pattern. The similarity in polypeptide composition between endoplasmic-reticulum and glyoxysomal membranes is discussed in relation to glyoxysome biogenesis.
通过蔗糖密度梯度离心法,从萌发的蓖麻(Ricinus communis)胚乳匀浆中分离出微粒体组分、乙醛酸循环体和线粒体。对这些细胞组分的洗涤膜制剂进行十二烷基硫酸钠/聚丙烯酰胺凝胶电泳分析。在相应的发育阶段,内质网和乙醛酸循环体膜在多肽组成上惊人地相似,从3日龄组织中分离出的膜中至少存在16种多肽。向完整的胚乳组织供应[35S]甲硫氨酸会导致所有膜多肽被标记,内质网中的比放射性高于乙醛酸循环体膜中相应多肽的比放射性。用脱氧胆酸钠溶液洗涤这些膜会大量溶解蛋白质成分,但分子量为55000的主要多肽除外。线粒体膜制剂在多肽分子量分布和[35S]甲硫氨酸标记模式上与内质网和乙醛酸循环体的不同。本文结合乙醛酸循环体的生物发生讨论了内质网和乙醛酸循环体膜在多肽组成上的相似性。