Expression of human leukotriene A4 hydrolase cDNA in Escherichia coli

The cDNA clone encoding human leukotriene A4 hydrolase was inserted into a vector pUC9 and expressed in Escherichia coli as a fusion protein containing the first 10 amino acid residues derived from a vector. The leukotriene A4 hydrolase activity was recovered in the soluble fraction of the transformants. The purified enzyme showed kinetic properties similar to the native enzyme, including inactivation by the substrate and sulfhydryl-modifying reagents. The results demonstrate that a protein with an Mr of 70,000 was expressed in Escherichia coli with a full enzyme activity and structural fidelity. Acquisition of the expression system makes it feasible to elucidate the reaction mechanism of the enzyme.