锰超氧化物歧化酶（SOD-3）在体外的合成、导入及加工并进入玉米线粒体的过程。

In vitro synthesis, importation and processing of Mn-superoxide dismutase (SOD-3) into maize mitochondria.

作者信息

White J A, Scandalios J G

机构信息

Department of Genetics, North Carolina State University, Raleigh 27695-7614.

出版信息

Biochim Biophys Acta. 1987 Oct 8;926(1):16-25. doi: 10.1016/0304-4165(87)90178-4.

DOI:10.1016/0304-4165(87)90178-4

PMID:2443181

Abstract

In vitro translation of maize scutellar polysome-bound RNA and poly(A)+RNA produces a precursor for the mitochondrial superoxide dismutase (SOD-3) of maize, which can be immunoprecipitated with SOD-3 monospecific antibodies. The precursor SOD-3 (preSOD-3) has both a greater molecular weight and a more positive isoelectric point than the mature (purified) SOD-3. These differences were not observed for the cytosolic isozyme (SOD-4) which was similarly synthesized and isolated. PreSOD-3 specifically associates with maize mitochondria when incubated in vitro, whereas SOD-4 does not. The ionophore valinomycin (at concentrations of over 1 microM) inhibits the uptake of preSOD-3 into mitochondria. The integrity of the mitochondrial preparations was determined by assay of oxygen consumption, citrate synthase, and cytochrome-c oxidase activity.

摘要

对玉米盾片多核糖体结合RNA和聚腺苷酸加尾RNA（poly(A)+RNA）进行体外翻译，可产生玉米线粒体超氧化物歧化酶（SOD - 3）的前体，该前体可用SOD - 3单特异性抗体进行免疫沉淀。前体SOD - 3（preSOD - 3）的分子量比成熟（纯化）的SOD - 3更大，等电点也更偏正。对于以类似方式合成和分离的胞质同工酶（SOD - 4），未观察到这些差异。体外孵育时，preSOD - 3特异性地与玉米线粒体结合，而SOD - 4则不然。离子载体缬氨霉素（浓度超过1 microM）会抑制preSOD - 3进入线粒体。通过检测氧气消耗、柠檬酸合酶和细胞色素c氧化酶活性来确定线粒体制剂的完整性。