SP-22 is a mitochondrial antioxidant protein in @entity291 adrenal cortex. The protein is homologous to @entity31513 peroxidase and other antioxidant proteins. It protects radical-sensitive enzymes from oxidative damage by a radical-generating system ( @entity8798 / @entity3902 ) in the presence of a small amount of serum. In this study we purified a second mitochondrial protein with Mr 11,777, which cooperates with SP-22 to protect @entity1160 synthetase and other proteins from @entity8798 / @entity3902 -mediated damage. Without SP-22, the protein had no protecting activity. We determined @entity535 and @entity377 sequences of the protein and its cDNA, respectively, and found that it was a protein of the @entity31513 family. The protein, designated as @entity70307 ( @entity70307 ), had a presequence composed of 59 @entity1522 that seemed to be a mitochondrial targeting signal. Mitochondrial extract prepared from adrenal cortex contained @entity1110 -dependent @entity8865 (Nbs2) reductase activity. The enzyme was thought to have @entity31513 reductase activity, since the Nbs2-reducing activity was stimulated by @entity70307 . We partially purified the Nbs2 reductase from @entity291 adrenocortical mitochondria. In the presence of the partially purified reductase, @entity70307 , and @entity1110 , SP-22 showed the activity to protect @entity7672 against @entity9050 -induced damage. Furthermore, with the three protein components (Nbs2 reductase, @entity70307 , and SP-22) @entity1110 was oxidized in the presence of @entity273 or @entity2469 . The oxidation of @entity1110 was concomitant with the disappearance of an equimolar amount of @entity273 . Without any one of the protein components no hemoglobin-protecting and @entity2625 -dependent @entity1110 -oxidizing activities were observed. From these results we concluded that SP-22 is @entity31513 -dependent @entity2625 reductase or so-called @entity31513 peroxidase in mitochondria from the adrenal cortex.

SP-22 is a XXXX -dependent @entity2625 reductase in mitochondria.

@entity1522 :: ('CHEBI:33709', 'Chemical') :: ['amino acids'] @entity31513 :: ('280950(Tax:9913)', 'Gene') :: ['thioredoxin'] @entity8798 :: ('CHEBI:29033', 'Chemical') :: ['Fe2+'] @entity1160 :: ('CHEBI:28300', 'Chemical') :: ['glutamine'] @entity535 :: ('CHEBI:33704', 'Chemical') :: ['amino acid'] @entity8865 :: ('MESH:D004228', 'Chemical') :: ["5,5'dithiobis(2-nitrobenzoic acid)"] @entity3902 :: ('MESH:D004229', 'Chemical') :: ['dithiothreitol'] @entity377 :: ('CHEBI:36976', 'Chemical') :: ['nucleotide'] @entity2625 :: ('CHEBI:44785', 'Chemical') :: ['peroxide'] @entity1110 :: ('MESH:D009249', 'Chemical') :: ['NADPH'] @entity273 :: ('MESH:D006861', 'Chemical') :: ['hydrogen peroxide'] @entity70307 :: ('281557(Tax:9913)', 'Gene') :: ['mt-Trx', 'mitochondrial thioredoxin'] @entity7672 :: ('CHEBI:7861', 'Chemical') :: ['oxyhemoglobin'] @entity2469 :: ('MESH:D020122', 'Chemical') :: ['tert-butyl hydroperoxide'] @entity291 :: ('9913', 'Species') :: ['bovine'] @entity9050 :: ('CHEBI:38290', 'Chemical') :: ['ascorbate']
@entity31513 :: (280950(Tax:9913),Gene) :: ['thioredoxin']
