THE CDNA SEQUENCE ENCODING BOVINE SP-22, A NEW DEFENSE SYSTEM AGAINSTREACTIVE OXYGEN SPECIES IN MITOCHONDRIA

We have isolated cDNA clones coding SP-22, an antioxidant protein in m itochondria, from a bovine adrenal medulla cDNA library constructed wi th lambda gt11. The largest clone contained the entire coding sequence for mature SP-22. Since the isolated cDNA clones lacked 5'- and 3'-en ds, we determined the sequences of both ends by the ''Rapid Amplificat ion of cDNA Ends (RACE)'' tecnique. The deduced amino acid sequence of the mature protein region was the same as that determined by protein sequencing. Since SP-22 had a mitochondrial targetting signal, its mit ochondrial localization was confirmed.