In vitro synthesis, importation and processing of Mn-superoxide dismutase (SOD-3) into maize mitochondria.
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.
D000818:Animals; D000911:Antibodies, Monoclonal; D008928:Mitochondria / Q000201:enzymology*; D010101:Oxygen Consumption; D010944:Plants / Q000201:enzymology*; D011061:Poly A / Q000235:genetics; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism; D013482:Superoxide Dismutase / Q000096:biosynthesis / Q000235:genetics*; D003313:Zea mays / Q000201:enzymology
D000911:Antibodies, Monoclonal; D012333:RNA, Messenger; D011061:Poly A; D012313:RNA; D013482:Superoxide Dismutase