Purification of glyoxalase I from onion bulbs and molecular cloning of its cDNA.
Glyoxalase I was highly purified from onion bulbs by DEAE-cellulose, hydroxyapatite, and S-hexylglutathione-agarose column chromatography. With 356 micromol min(-1) mg(-1) protein, the specific enzymatic activity of the purified enzyme is the highest reported to date in plants. The purified enzyme showed a single major band with a relative molecular mass of approximately 25,000 on SDS-PAGE. A cDNA encoding glyoxalase I was cloned and sequenced. Sequence comparison suggested that it is to be classified as a short-type glyoxalase I. The expression pattern of glyoxalase I in healthy onion plants and responses to various stresses were examined by Western blotting. Glyoxalase I exists at high concentration in roots, young bulbs, mature bulbs, and mature leaves, the highest concentration being in mature bulbs. Up-regulation of glyoxalase I and glyoxalase II enzyme activities were observed in response to various stresses, and an increase in Gly I protein was also seen by immunoblotting. Our results suggest an important role of the glyoxalase I gene in the plant abiotic stress response.
Hossain
Mohammad Anwar
MA
Department of Applied Biological Science, Laboratory of Plant Stress Responses, Faculty of Agriculture, Kagawa University, Miki-cho, Kita-gun, Kagawa 761-0795, Japan.
Fujita
Masayuki
M
D000595:Amino Acid Sequence; D015153:Blotting, Western; D002853:Chromatography, Liquid / Q000379:methods; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D007791:Lactoylglutathione Lyase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D019697:Onions / Q000201:enzymology*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D007791:Lactoylglutathione Lyase