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 IP TG, 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-ami no-acid polypeptide. Edman analysis indicates that the predicted N-ter minal methionine is lost posttranslationally to yield a 19407-Da prote in. Mass spectrometry of the intact protein, and of the peptides gener ated from treatment with CNBr, does not indicate any additional post-t ranslational modifications of the enzyme. Contrary to previous conclus ions, there are no major regions of dissimilarity between the human an d bacterial enzymes.