Human Microsomal Prostaglandin E Synthase-1

Human, microsomal, and glutathione-dependent prostaglandin (PG) E synthase-1 (mPGES-1) was expressed with a histidine tag in Escherichia coli. mPGES-1 was purified to apparent homogeneity from Triton X-100-solubilized bacterial extracts by a combination of hydroxyapatite and immobilized metal affinity chromatography. The purified enzyme displayed rapid glutathione-dependent conversion of PGH2 to PGE2 (Vmax; 170 μmol min–1 mg–1) and high kcat/Km (310 mm–1 s–1). Purified mPGES-1 also catalyzed glutathione-dependent conversion of PGG2 to 15-hydroperoxy-PGE2 (Vmax; 250 μmol min–1 mg–1). The formation of 15-hydroperoxy-PGE2 represents an alternative pathway for the synthesis of PGE2, which requires further investigation. Purified mPGES-1 also catalyzed glutathione-dependent peroxidase activity toward cumene hydroperoxide (0.17 μmol min–1 mg–1), 5-hydroperoxyeicosatetraenoic acid (0.043 μmol min–1 mg–1), and 15-hydroperoxy-PGE2 (0.04 μmol min–1 mg–1). In addition, purified mPGES-1 catalyzed slow but significant conjugation of 1-chloro-2,4-dinitrobenzene to glutathione (0.8 μmol min–1 mg–1). These activities likely represent the evolutionary relationship to microsomal glutathione transferases. Two-dimensional crystals of purified mPGES-1 were prepared, and the projection map determined by electron crystallography demonstrated that microsomal PGES-1 constitutes a trimer in the crystal, i.e. an organization similar to the microsomal glutathione transferase 1. Hydrodynamic studies of the mPGES-1-Triton X-100 complex demonstrated a sedimentation coefficient of 4.1 S, a partial specific volume of 0.891 cm3/g, and a Stokes radius of 5.09 nm corresponding to a calculated molecular weight of 215,000. This molecular weight, including bound Triton X-100 (2.8 g/g protein), is fully consistent with a trimeric organization of mPGES-1. Human, microsomal, and glutathione-dependent prostaglandin (PG) E synthase-1 (mPGES-1) was expressed with a histidine tag in Escherichia coli. mPGES-1 was purified to apparent homogeneity from Triton X-100-solubilized bacterial extracts by a combination of hydroxyapatite and immobilized metal affinity chromatography. The purified enzyme displayed rapid glutathione-dependent conversion of PGH2 to PGE2 (Vmax; 170 μmol min–1 mg–1) and high kcat/Km (310 mm–1 s–1). Purified mPGES-1 also catalyzed glutathione-dependent conversion of PGG2 to 15-hydroperoxy-PGE2 (Vmax; 250 μmol min–1 mg–1). The formation of 15-hydroperoxy-PGE2 represents an alternative pathway for the synthesis of PGE2, which requires further investigation. Purified mPGES-1 also catalyzed glutathione-dependent peroxidase activity toward cumene hydroperoxide (0.17 μmol min–1 mg–1), 5-hydroperoxyeicosatetraenoic acid (0.043 μmol min–1 mg–1), and 15-hydroperoxy-PGE2 (0.04 μmol min–1 mg–1). In addition, purified mPGES-1 catalyzed slow but significant conjugation of 1-chloro-2,4-dinitrobenzene to glutathione (0.8 μmol min–1 mg–1). These activities likely represent the evolutionary relationship to microsomal glutathione transferases. Two-dimensional crystals of purified mPGES-1 were prepared, and the projection map determined by electron crystallography demonstrated that microsomal PGES-1 constitutes a trimer in the crystal, i.e. an organization similar to the microsomal glutathione transferase 1. Hydrodynamic studies of the mPGES-1-Triton X-100 complex demonstrated a sedimentation coefficient of 4.1 S, a partial specific volume of 0.891 cm3/g, and a Stokes radius of 5.09 nm corresponding to a calculated molecular weight of 215,000. This molecular weight, including bound Triton X-100 (2.8 g/g protein), is fully consistent with a trimeric organization of mPGES-1. Prostaglandin (PG) 1The abbreviations used are: PG, prostaglandin; CDNB, 1-chloro-2,4-dinitrobenzene; GST, glutathione S-transferase; His6-mPGES-1, His6-tagged human prostaglandin E synthase; 5-HpETE, 5-hydroperoxyeicosatetraenoic acid; LT, leukotriene; MAPEG, membrane-associated proteins in eicosanoid and glutathione metabolism; MGST, microsomal glutathione transferase; mPGES-1, microsomal prostaglandin E synthase-1; PGES, prostaglandin E synthase; PGHS, prostaglandin H synthase; HPLC, high pressure liquid chromatography; AU, absorbance units; 5-HETE, 5-hydroxyeicosatetraenoic acid. E2 is a prostanoid with potent biological functions; among those functions, its role as a mediator of pain and fever in inflammatory reactions is considered of major importance (1Mnich S.J. Veenhuizen A.W. Monahan J.B. Sheehan K.C. Lynch K.R. Isakson P.C. Portanova J.P. J. Immunol. 1995; 155: 4437-4444PubMed Google Scholar, 2Portanova J.P. Zhang Y. Anderson G.D. Hauser S.D. Masferrer J.L. Seibert K. Gregory S.A. Isakson P.C. J. Exp. Med. 1996; 184: 883-891Crossref PubMed Scopus (380) Google Scholar, 3Ushikubi F. Segi E. Sugimoto Y. Murata T. Matsuoka T. Kobayashi T. Hizaki H. Tuboi K. Katsuyama M. Ichikawa A. Tanaka T. Yoshida N. Narumiya S. Nature. 1998; 395: 281-284Crossref PubMed Scopus (587) Google Scholar, 4Narumiya S. Sugimoto Y. Ushikubi F. Physiol. Rev. 1999; 79: 1193-1226Crossref PubMed Scopus (0) Google Scholar). The biosynthesis of PGE2 from arachidonic acid is catalyzed in a sequential action by PGH synthase (PGHS) forming first the endoperoxide PGG2 and then PGH2 by reduction. Subsequently, PGE synthase (PGES) (EC 5.3.99.3) converts PGH2 into PGE2 (5Smith W.L. Adv. Exp. Med. Biol. 1997; 400: 989-1011Google Scholar). Two forms of PGHS exist, PGHS-1 and PGHS-2, with similar enzymatic properties but distinctly different biological functions. PGHS-1 is constitutively expressed in many cells and organs and takes part in housekeeping functions such as the regulation of vascular homeostasis. PGHS-2, in contrast, is strongly induced in response to proinflammatory stimuli and takes part in various pathophysiological events (6Dubois R.N. Abramson S.B. Crofford L. Gupta R.A. Simon L.S. Van de Putte L.B.A. Lipsky P.E. FASEB J. 1998; 12: 1063-1073Crossref PubMed Scopus (2231) Google Scholar, 7Smith W.L. DeWitt D.L. Garavito R.M. Annu. Rev. Biochem. 2000; 69: 145-182Crossref PubMed Scopus (2477) Google Scholar). PGES activity, in most cases glutathione (GSH)-dependent, has been detected both in microsomal and cytosolic fractions of various cells, and apparently, more than one form of PGES exist (8Tanaka Y. Ward S.L. Smith W.L. J. Biol. Chem. 1987; 262: 1374-1381Abstract Full Text PDF PubMed Google Scholar, 9Ogorochi T. Ujihara M. Narumiya S. J. Neurochem. 1987; 48: 900-909Crossref PubMed Scopus (56) Google Scholar, 10Watanabe K. Kurihara K. Tokunaga Y. Hayaishi O. Biochem. Biophys. Res. Commun. 1997; 235: 148-152Crossref PubMed Scopus (72) Google Scholar, 11Tanioka T. Nakatani Y. Semmyo N. Murakami M. Kudo I. J. Biol. Chem. 2000; 275: 32775-32782Abstract Full Text Full Text PDF PubMed Scopus (635) Google Scholar, 12Beuckmann C.T. Fujimori K. Urade Y. Hayaishi O. Neurochem. Res. 2000; 25: 733-738Crossref PubMed Scopus (80) Google Scholar). Microsomal, inducible PGES-1 (mPGES-1) is a member of the membrane-associated proteins in eicosanoid and glutathione metabolism (MAPEG) superfamily (13Jakobsson P.-J. Morgenstern R. Mancini J. Ford-Hutchinson A. Persson B. Protein Sci. 1999; 8: 689-692Crossref PubMed Scopus (304) Google Scholar, 14Jakobsson P.-J. Morgenstern R. Mancini J. Ford-Hutchinson A. Persson B. Am. J. Med. 2000; PubMed Scopus Google Scholar). The was as a of the for in The of proteins with and functions such as glutathione transferase and mPGES-1 (13Jakobsson P.-J. Morgenstern R. Mancini J. Ford-Hutchinson A. Persson B. Protein Sci. 1999; 8: 689-692Crossref PubMed Scopus (304) Google Scholar, 14Jakobsson P.-J. Morgenstern R. Mancini J. Ford-Hutchinson A. Persson B. Am. J. Med. 2000; PubMed Scopus Google Scholar). member is microsomal glutathione transferase which a of reactions in of and from R. L. H. B. H. I. Morgenstern R. N. H. Van and Scholar). mPGES-1 was and as a of with the acid functions been the was to as (13Jakobsson P.-J. Morgenstern R. Mancini J. Ford-Hutchinson A. Persson B. Protein Sci. 1999; 8: 689-692Crossref PubMed Scopus (304) Google Scholar). The was also as a K. Y. J.L. B. Nature. 1997; PubMed Scopus Google and to as and as the mPGES-1 P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google Scholar). is to mPGES-1, its to the conversion of PGH2 to PGE2, and as been than the for mPGES-1 expressed in Escherichia and bacterial fractions mPGES-1 displayed a PGES activity P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google Scholar). cytosolic PGES that is with PGHS-1 has also been T. Nakatani Y. Semmyo N. Murakami M. Kudo I. J. Biol. Chem. 2000; 275: 32775-32782Abstract Full Text Full Text PDF PubMed Scopus (635) Google Scholar). cytosolic glutathione that catalyzed PGES activity been purified from human T. Ujihara M. Narumiya S. J. Neurochem. 1987; 48: 900-909Crossref PubMed Scopus (56) Google Scholar). cytosolic glutathione of the that also displayed PGES activity were purified from human C.T. Fujimori K. Urade Y. Hayaishi O. Neurochem. Res. 2000; 25: 733-738Crossref PubMed Scopus (80) Google Scholar). PGES activity in the of has been in microsomal fractions from and and the of a PGES was K. Kurihara K. Tokunaga Y. Hayaishi O. Biochem. Biophys. Res. Commun. 1997; 235: 148-152Crossref PubMed Scopus (72) Google Scholar). PGES was purified from K. Kurihara K. T. Biophys. 1999; PubMed Scopus Google and the corresponding was and purified N. Y. H. K. K. M. S. K. Biochem. Biophys. Res. Commun. PubMed Scopus Google Scholar). that more than one of microsomal PGE PGES-1 was induced in cells, a with the proinflammatory P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google Scholar). The of mPGES-1 and PGE2 by in cells was demonstrated S. P.-J. J. Biochem. 2000; PubMed Scopus Google to in with the of studies M. H. T. Semmyo N. Nakatani Y. F. T. M. A. S. Kudo I. J. Biol. Chem. 2000; 275: Full Text Full Text PDF PubMed Scopus Google Scholar, M. S. A. P.-J. A. Nature. PubMed Scopus Google Scholar, S. H. M. P.-J. Crofford J. Immunol. PubMed Scopus Google Scholar, K. K. T. K. S. H. Y. Kobayashi S. J. PubMed Google Scholar, K. J. R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google in various that mPGES-1 and regulation with the inducible in response to proinflammatory mPGES-1 was also demonstrated to in K. Zhang F. P.-J. K. Res. Google and K. R.A. P.-J. R.A. K. Res. Google S.A. Anderson R.A. J. PubMed Google as as in F. B. M. M. A. S. F. F. A. PubMed Scopus Google Scholar). The role of mPGES-1 in and to PGES has been the of many by for with (8Tanaka Y. Ward S.L. Smith W.L. J. Biol. Chem. 1987; 262: 1374-1381Abstract Full Text PDF PubMed Google Scholar, 9Ogorochi T. Ujihara M. Narumiya S. J. Neurochem. 1987; 48: 900-909Crossref PubMed Scopus (56) Google Scholar, 10Watanabe K. Kurihara K. Tokunaga Y. Hayaishi O. Biochem. Biophys. Res. Commun. 1997; 235: 148-152Crossref PubMed Scopus (72) Google with the of the enzyme the In to apparent in and a projection map the of human mPGES-1. mPGES-1 was as P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google Scholar). and were from was from PGE2, 5-HpETE, and were from glutathione and Triton X-100 and were from high and were from and were from were from were from J. T. was from were of and from of was by of arachidonic acid with of the microsomal of of the as M. J. T. B. Sci. S. A. PubMed Scopus Google Scholar). was used as electron was by a of acid. PGG2 was in an the was from prostaglandin M. J. T. B. Sci. S. A. PubMed Scopus Google by by was by of prostaglandin E2 M. J. Biol. Chem. Full Text PDF PubMed Google by by and of and of the for the human mPGES-1 into the has been P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google Scholar). of an tag forming a of the was by In the the including the first of the expressed was to by a the The His6-tagged human mPGES-1 was expressed from the in E. cells the J. Biol. PubMed Scopus Google of cells in and was into of and and The was with the was the was of was induced by the of and the was for were by and with The were further of were and in a for a from of The cells were by which of expressed from the J. Biol. PubMed Scopus Google Scholar). was by the of and and for The was by from a The was by for The was then for and the were in and of E. was and proteins were in a and Triton X-100 for with a of was by for The was a and of from a was and in of These cells were by the of the as The was in an by the in the was by the of an volume of Triton X-100 and was for The was from by and as for the of was purified in a combination of hydroxyapatite by immobilized metal affinity chromatography. was with hydroxyapatite of that been with Triton Triton X-100 was used to the of the to of proteins in the affinity a the hydroxyapatite was by a and the was and by and The from the hydroxyapatite was a that been with and with Triton X-100 a of the was with proteins were was to bound the that bound to the affinity was by a of The was into and Triton X-100 a a of PGES activity was in of PGH2 in and purified His6-mPGES-1, as S. P.-J. J. Biochem. 2000; PubMed Scopus Google Scholar). Triton X-100 was in investigation. Triton X-100 is than for mPGES-1 were purified by and with of by the was in of the for glutathione was activity was with a of PGH2 and The were the from of as S. P.-J. J. Biochem. 2000; PubMed Scopus Google Scholar). of PGG2 to was as for mPGES-1 in of and of purified The was by the of of and of the to by for to the the formation of PGE2 and an was by HPLC, with The were the from of activity toward 5-hydroperoxyeicosatetraenoic acid was in of and of purified The was by of of acid. of was then and the was by for was by with a from The was and acid by The was and the were the nm from of and activity with cumene hydroperoxide as was determined by a with purified His6-mPGES-1, cumene hydroperoxide in and an of glutathione as the in nm A. PubMed Scopus Google Scholar). activity toward 15-hydroperoxy-PGE2 was as for PGG2 with purified and 15-hydroperoxy-PGE2 was nm J. Biol. Chem. Full Text PDF PubMed Google in Triton 1-chloro-2,4-dinitrobenzene and purified The also that was the for The conjugation of to was from the enzymatic conjugation different enzyme a specific activity with an S.D. of than and of of enzymatic reactions were calculated the and activity were calculated by the of S.D. of for the for PGG2 that of the in Triton X-100 was to by to of the H. The Scholar, PubMed Scopus Google Scholar). as from of by electron and were to by the J. Biol. PubMed Scopus Google Scholar, T. Murata K. K. Y. Y. J. 1999; 48: PubMed Scopus Google a as The were and in a the were a electron were in a corresponding to the The were to of as R. J. F. Scopus Google from the R.A. R. Smith J. Biol. 1996; PubMed Scopus Google Scholar). sedimentation coefficient of the mPGES-1-Triton X-100 complex was determined by of purified with of and of in a volume of of a Triton and were used as with sedimentation of and S, was in a for were from the of the with a a and were for activity and These fractions were for PGES activity as and the of the was was determined from the absorbance and was by to and Biochem. PubMed Scopus Google to the high in partial specific volume of the mPGES-1-Triton X-100 complex was determined by of purified was to a Triton The were in a for both and to that been of were and as Stokes Stokes radius of the mPGES-1-Triton X-100 complex was determined by a of in Triton and of purified was the with in of from was used with the and of were and with to and proteins and PGES from absorbance nm and activity were used to of the has been to significant of The Stokes radius was to the from Triton to from were with to both Triton X-100 and The was with a Triton X-100 in to the absorbance of Triton In to the of Triton X-100 bound to mPGES-1, the coefficient for mPGES-1 nm was calculated F. L. T. Protein Sci. 1995; PubMed Scopus Google Scholar). The absorbance of the Triton X-100 was from the absorbance of the both mPGES-1 and Triton The absorbance of mPGES-1 was calculated the and the of was determined by Biochem. PubMed Scopus Google Scholar). The absorbance from Triton X-100 bound to mPGES-1, and the corresponding of Triton X-100 was determined by the of a the of Triton X-100 to the of in the of in of molecular of a complex calculated from the R. with to is the molecular is the of is the sedimentation a is the is is the partial specific and is the of and was in as Nature. PubMed Scopus Google Scholar). Protein were detected by and mPGES-1 was as S. P.-J. J. Biochem. 2000; PubMed Scopus Google Scholar). human mPGES-1 was expressed in E. as for the P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google Scholar). of was of but the specific PGES activity was fractions from cells induced for of were in Triton was by and the of was by the was for the was and in the PGES activity was in in the of and The of was for a for the PGES activity and was in The PGES activity in for a in the of and of the activity as of PGE2 and of the activity determined In the of and the PGES activity in was purified to apparent homogeneity from by a combination of hydroxyapatite by immobilized metal affinity a with The was with a of hydroxyapatite by the from the hydroxyapatite the was the and the bound proteins by a of was then as a by a of The was to by the high The were fractions as for the In a purified to apparent homogeneity was The was of purified from fractions and from of The purified was as mPGES-1 by mPGES-1 and PGES activity The molecular weight of the purified was calculated from its to to which is in with the molecular weight of human were from a a the purified as for a the of in the fractions were determined by of from to of the were in different of fractions from of from bacterial molecular weight from hydroxyapatite from with were by and and of purified with and molecular weight with mPGES-1 and of in bacterial Purified and from cells were by and as The was determined by and the was for to of the purified The purified catalyzed glutathione-dependent conversion of PGH2 to was with prepared, and for with bacterial The activity of the purified enzyme was to of the activity was with the and of the activity enzyme that was of of PGES activity with the purified for were to of the by mPGES-1 in the been determined by a similar activity as the purified This strongly that the is in its and of PGH2 into human toward PGH2 in the of The activity was by in a and PGES activity detected in the of and for PGH2 and in and specific is in was by such as the purified was for of purified with in the of for the PGES activity by for mPGES-1 in a activities of mPGES-1 in a of PGG2 into the for human catalyzed the of PGG2 into Purified was with PGG2 in the of of a major of 15-hydroperoxy-PGE2 was The corresponding demonstrated a of 15-hydroperoxy-PGE2 the enzyme was in the of the of but first by formation of 15-hydroperoxy-PGE2 was of is a formation of PGE2 and in the in the His6-mPGES-1, PGE2 but is that PGG2 constitutes a for mPGES-1, further demonstrated a similar toward PGG2 as with PGH2 and for PGG2 in and specific in catalyzed the of 15-hydroperoxy-PGE2 a with the of PGG2 to 15-hydroperoxy-PGE2 and to the properties of PGG2 and the as and the of into the corresponding 5-HpETE, and cumene hydroperoxide as for Purified catalyzed a specific glutathione peroxidase activity toward peroxidase activity the enzyme for also catalyzed the of 15-hydroperoxy-PGE2 in the of a than the of 15-hydroperoxy-PGE2 purified catalyzed peroxidase activity toward cumene hydroperoxide (0.17 μmol min–1 a the enzyme was for which activity toward was with purified that the enzyme a but significant activity a purified was for which activity The activity to CDNB, which is the of and an apparent for of purified with in the of for of the enzyme synthase activity detected the purified was with and Two-dimensional crystals of human a The were consistent with projection with an of to a of The to the a and of the to and of in and as in The projection map was by from from the electron of from in projection for and for in projection for and for 1. in a The sedimentation partial specific and Stokes radius of the mPGES-1-Triton X-100 complex were determined by the of and the sedimentation coefficient of the mPGES-1-Triton X-100 complex was to 4.1 and the partial specific volume was 0.891 which to a of and a of demonstrated in which one of the with Triton X-100 from the mPGES-1-Triton X-100 complex with the The of were the Stokes of the and the Stokes radius of the mPGES-1-Triton X-100 complex was to 5.09 was also with which were by Triton X-100 in the These were then into the and the molecular weight of the mPGES-1-Triton X-100 complex was calculated to the of bound in the mPGES-1-Triton X-100 absorbance and was the fractions from the immobilized metal affinity the and the coefficient of mPGES-1 F. L. T. Protein Sci. 1995; PubMed Scopus Google the absorbance for mPGES-1 was calculated to The and the calculated for mPGES-1 was from the absorbance of the mPGES-1-Triton X-100 complex and the of bound to mPGES-1 in a of to a of Triton X-100 to which a of of Triton of mPGES-1 a trimer mPGES-1 and of and the weight of the complex with a trimeric PGES-1 was purified for studies of and a for bacterial of human microsomal PGES-1 that was P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google as a of for of the human mPGES-1 was by Triton X-100 with enzymatic activity in the The is for enzymatic activity, but also has an apparent for the the activity is and for a the is in the of in the of The of also a enzyme activity of the mPGES-1 a tag the of the for affinity In combination with hydroxyapatite the as a first purified to apparent homogeneity a and were was used as the the of the for the and also the was from The of in the bacterial to of the is high a and the of the Purified was and to in the purified that been for of major of microsomal PGES-1 has been the of the The of Triton X-100 as and the of and the to This and and The of purified was 170 μmol min–1 for the conversion of PGH2 to PGE2 which is than prostaglandin for PGH2 is with the and further studies to the in a major role for the microsomal PGES-1 in the of PGE2 in for purified prostaglandin PGES activities PGES PGES PGES PGES PGES activities cytosolic activities activities in a Purified catalyzed a but significant activity cytosolic that been as PGE such as the and in the human C.T. Fujimori K. Urade Y. Hayaishi O. Neurochem. Res. 2000; 25: 733-738Crossref PubMed Scopus (80) Google and the forms of cytosolic T. Ujihara M. Narumiya S. J. Neurochem. 1987; 48: 900-909Crossref PubMed Scopus (56) Google also catalyzed activity toward PGES activities were Purified for CDNB, and the enzyme with the of that mPGES-1 expressed in E. activity toward in bacterial P.-J. S. Morgenstern R. B. Sci. S. A. 1999; PubMed Scopus Google an that by the activity of the the human and also activity, and the activity of its relationship to in of the relationship to was that purified catalyzed peroxidase activity toward cumene the specific activity determined (0.17 μmol min–1 mg–1) was to that determined with R. E. J. J. T. Morgenstern R. Biochem. J. 1995; PubMed Scopus Google Scholar). Purified catalyzed a peroxidase activity toward 5-HpETE, an with both and P.-J. Morgenstern R. Mancini J. Ford-Hutchinson A. Persson B. Am. J. Med. 2000; PubMed Scopus Google Scholar). that purified the conversion of PGG2 to 15-hydroperoxy-PGE2 in the of of the hydroperoxide into PGE2 catalyzed by mPGES-1 a The to the PGE2 from 15-hydroperoxy-PGE2 in the of is is a but is in most cells high by is likely to in W.L. Biophys. PubMed Scopus Google Scholar). is more that the of 15-hydroperoxy-PGE2 into PGE2 is catalyzed by glutathione-dependent Sci. 2000; PubMed Google Scholar, E. Biophys. PubMed Scopus (635) Google by the peroxidase activity of the specific activity and for the enzymatic conversion of PGG2 to 15-hydroperoxy-PGE2 by were than for the PGE2 formation from PGH2 and that the formation of PGE2 from PGG2 PGG2 into PGH2 by the peroxidase activity of PGHS and then to PGE2 catalyzed by mPGES-1, first into 15-hydroperoxy-PGE2 by mPGES-1 by to PGE2 by in a as has been B. M. of the Prostaglandin Scholar). mPGES-1, such as the also been to PGG2 as S. J. Biol. Chem. Full Text PDF PubMed Google Scholar). PGHS-1 and the and peroxidase but The peroxidase a the the takes in the of the PGG2 to to the peroxidase the of the enzyme W.L. DeWitt D.L. Garavito R.M. Annu. Rev. Biochem. 2000; 69: 145-182Crossref PubMed Scopus (2477) Google Scholar). the and J. Biol. Chem. Full Text PDF PubMed Google of PGG2 from the to the peroxidase in microsomal in the with both mPGES-1 and in the a for PGG2 and further studies to the specific of the in the and mPGES-1. In such a PGG2 to mPGES-1, which the formation of the 15-hydroperoxy-PGE2 is to and to This further from a M. J.P. A. Mancini Protein PubMed Scopus Google was of human mPGES-1 expressed in a for PGE synthase activity and that was In to a apparent for PGH2 with in the enzyme activity In the apparent was determined and M. N. Y. Urade Y. Hayaishi O. Biochem. Biophys. PubMed Scopus (72) Google a high for mPGES-1 expressed in E. which is in with These in further the in and cells, different In addition, significant but and peroxidase activities in to M. J.P. A. Mancini Protein PubMed Scopus Google that for the further of the mPGES-1 mPGES-1 forms crystals for electron The molecular weight of the in to the that of the in the map in to the projection of the to the of the The is which is with crystals of many mPGES-1 forms a trimer in the In the of different of crystals been The form has a the in the trimer I. Murata K. T. Morgenstern R. Y. H. J. Biol. 1999; PubMed Scopus Google Scholar, I. K. T. Murata K. Y. Y. Morgenstern R. H. J. 2000; PubMed Scopus Google the has a H. I. Morgenstern R. Murata M. T. K. Y. J. Biol. 1997; PubMed Scopus Google Scholar). The high of the displayed by that is in the projection map of mPGES-1. Hydrodynamic studies of the mPGES-1-Triton X-100 complex demonstrated properties similar to the X-100 complex R. J. Biochem. PubMed Scopus Google Scholar). mPGES-1 was to of Triton of The corresponding for is in with that Triton X-100 and is K. 1995; Scopus Google Scholar). the by mPGES-1 is consistent with a more from The of bound to mPGES-1 and the calculated of the molecular weight a trimeric of mPGES-1. In purified human microsomal PGES-1 to apparent homogeneity with high activity of the In to one of the most human PGE which in with and with its importance in eicosanoid pathophysiological purified the conversion of PGG2 to 15-hydroperoxy-PGE2 with high in the of as as of crystals by electron crystallography a projection a trimeric organization of mPGES-1. The calculated molecular weight from studies to the for a complex the trimeric is