Goldman B M, Blobel G
Proc Natl Acad Sci U S A. 1978 Oct;75(10):5066-70. doi: 10.1073/pnas.75.10.5066.
The intracellular site of synthesis of two peroxisomal enzymes of rat liver, uricase (urate:oxygen oxidoreductase, EC 1.7.3.3) and catalase (hydrogen peroxide:hydrogen peroxide oxidoreductase, EC 1.11.1.6), has been localized on free ribosomes and not membrane-bound ribosomes. Free polysomes and membrane-bound polysomes, prepared by classical cell fractionation techniques from rat liver, were incubated for protein synthesis in a cell-free system derived from rabbit reticulocytes. Characterization of the total translation products by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, as well as by immunoprecipitation with anti-rat albumin anti-serum, confirmed that good separation of the two polysome classes was achieved. Uricase and catalase were immunoprecipitable from translation products directed by free polysomes or phenol-extracted free polysomal mRNA but not from products of membrane-bound polysomes. Furthermore, unlike albumin, nascent uricase and catalase were not cotranslationally segregated by dog pancreas microsomal membranes. The results indicate that uricase and catalase are transferred to the interior of peroxisomes by a post-translational mechanism; an hypothesis is formulated here for the biogenesis of peroxisomes.
大鼠肝脏中两种过氧化物酶体酶，尿酸酶（尿酸：氧氧化还原酶，EC 1.7.3.3）和过氧化氢酶（过氧化氢：过氧化氢氧化还原酶，EC 1.11.1.6）的细胞内合成位点已定位在游离核糖体而非膜结合核糖体上。通过经典细胞分级分离技术从大鼠肝脏制备的游离多核糖体和膜结合多核糖体，在源自兔网织红细胞的无细胞系统中进行蛋白质合成孵育。通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳以及用抗大鼠白蛋白抗血清进行免疫沉淀对总翻译产物进行表征，证实实现了两类多核糖体的良好分离。尿酸酶和过氧化氢酶可从游离多核糖体或酚提取的游离多核糖体mRNA指导的翻译产物中免疫沉淀出来，但不能从膜结合多核糖体的产物中免疫沉淀出来。此外，与白蛋白不同，新生的尿酸酶和过氧化氢酶不会被犬胰腺微粒体膜共翻译分离。结果表明，尿酸酶和过氧化氢酶通过翻译后机制转移到过氧化物酶体内部；本文提出了一个关于过氧化物酶体生物发生的假说。
