Molecular cloning and characterization of the thiolesterase glyoxalase II from Arabidopsis thaliana

cDNA encoding glyoxalase II from Arabidopsis thaliana has been cloned and sequenced. The isolated 894 bp segment included a sequence of 774 bp encoding a protein with a calculated molecular mass of 28791 Da. The amino acid sequence deduced from the A. thaliana cDNA showed 54% identity with that of the human enzyme. Searches in databanks identified seven additional DNA sequences from different species with high similarity to glyoxalase II. Certain limited regions, one rich in histidine residues, shared 100% identity. A 29 kDa protein with an isoelectric point of 6.2 was obtained by heterologous expression of the A. thaliana cDNA in Escherichia coli. Homogeneous enzyme was obtained by affinity purification and its catalytic parameters with thiolesters of glutathione were similar to those for human glyoxalase II. The structural and functional similarities between glyoxalase II from A. thaliana and from human tissues suggest a common evolutionary origin.