Identification of cDNAS encoding plastid-targeted glutathione peroxidase.

A cDNA was isolated from pea leaf RNA which encodes a phospholipid hydroperoxide glutathione peroxidase (PHGPX; E.C. 1.1.1.1.9). The N-terminal section of this PHGPX encodes a recognisable chloroplast transit peptide. Efficient import in vitro of the pre-PHGPX protein into the stroma of isolated pea chloroplasts confirmed that the PHGPX is a chloroplast-located enzyme. The pea PHGPX has highly conserved homologues in Arabidopsis, citrus and Nicotiana sylvestris and the authors suggest that these proteins are also localised in the chloroplast and not in the cytosol as previously supposed.