Expression and purification of human mPGES-1 in E. coli and identification of inhibitory compounds from a drug-library.

Human microsomal prostaglandin E synthase-1 (mPGES-1) is a membrane associated protein that catalyzes the conversion of prostaglandin H(2) (PGH(2)) into prostaglandin E(2) (PGE(2)). In this study, the expression of human mPGES-1 in E. coli was significantly enhanced by modifying the utility of specific codons and the recombinant mPGES-1 was efficiently purified to homogeneity. The K(m) and V(max) of the purified enzyme were determined and the trimeric state characterized by chemical cross-linking with glutaraldehyde. The purified mPGES-1 was used for the screening of a chemical library of bioactive or drug compounds to identify novel inhibitors, and oxacillin and dyphylline were identified as moderately inhibiting mPGES-1 with IC(50) values of 100 and 200 microM, respectively. As these compounds competitively inhibited the catalysis of PGH(2), their binding sites appeared to be located near the PGH2 binding pocket.