THE GENE ENCODING GLYOXALASE-I FROM PSEUDOMONAS-PUTIDA - CLONING, OVEREXPRESSION, AND SEQUENCE COMPARISONS WITH HUMAN GLYOXALASE-I

The gene encoding glyoxalase I (GlxI) from Pseudomonas putida has been cloned into the high-expression plasmid pBTacI. In the presence of IPTG, JM109 cells transformed with this vector give expression levels of GlxI 4000-fold higher than wild-type Escherichia coli. Contrary to a previous report, the nucleotide sequence of the gene encodes a 173-amino-acid polypeptide. Edman analysis indicates that the predicted N-terminal methionine is lost posttranslationally to yield a 19407-Da protein. Mass spectrometry of the intact protein, and of the peptides generated from treatment with CNBr, does not indicate any additional post-translational modifications of the enzyme. Contrary to previous conclusions, there are no major regions of dissimilarity between the human and bacterial enzymes.