GLUTATHIONE S-TRANSFERASE FROM Hevea brasiliensis

Hevea brasiliencis has been the only commercial source of natural rubber. Glutathione S-transferases (GSTs) are a group of detoxification enzymes which protects plants and other organisms against wide variety of xenoboitic compounds. We have isolated a cDNA clone (called Hevea GST clone-1) that encodes a Phi class GST from the leaf tissues of Hevea. The Hevea GST clone-1 was sequenced. The cDNA was 954 bp in length and the longest open reading frame within the sequence starts with ATG at osition 82. The open reading frame contained 643 nucleotides and encoded a peptide of 219 amino acids with calculated mass of 24,853 Da. When compared with the well-documented rat liver classes of GST, the similarity was bserved for amino acids at position 50-95. As expected,the amino acid sequence at position 140-170, which is well conserved within the plant GSTs, had no clear similarity with the rat classes. The presence of Ser- 12 at the active site and the trio Glu-Ser-Arg at position 67,68,69 (part of G-site) shows that the sequence encoded by the glutathione S-transferase of Hevea clone-1 belongs to the plant specific class Phi.