Mutation of serine-516 in human prostaglandin G/H synthase-2 to methionine or aspirin acetylation of this residue stimulates 15-R-HETE synthesis.
Prostaglandin G/H synthase (PGHS) is a key enzyme in cellular prostaglandin (PG) synthesis and is the target of non-steroidal anti-inflammatory agents. PGHS occurs in two isoforms, termed PGHS-1 and PGHS-2. These isoforms differ in several respects, including their enzymatic activity following acetylation by aspirin. While PG synthesis by both isoforms is inhibited by aspirin, 15-R-hydroxyeicosatetraenoic acid (15-R-HETE) synthesis by PGHS-2, but not PGHS-1, is stimulated by preincubation with aspirin. We have mutated the putative aspirin acetylation site of hPGHS-2, and expressed the mutants in COS-7 cells using recombinant vaccinia virus. Enzyme activity and inhibitor sensitivity studies provide evidence that Ser516 is the aspirin acetylation site of human PGHS-2 and that substitution of a methionine residue at this position can mimic the effects of aspirin acetylation on enzyme activity.
Mancini
J A
JA
Department of Biochemistry and Molecular Biology, Merck Frosst Centre for Therapeutic Research, Kirkland, Que., Canada.
O'Neill
G P
GP
Bayly
C
C
Vickers
P J
PJ
D000107:Acetylation; D000818:Animals; D001241:Aspirin / Q000378:metabolism* / Q000494:pharmacology; D002460:Cell Line; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis*; D008715:Methionine / Q000737:chemistry; D008861:Microsomes / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D011451:Prostaglandin-Endoperoxide Synthases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011453:Prostaglandins / Q000096:biosynthesis; D012694:Serine / Q000737:chemistry
D006893:Hydroxyeicosatetraenoic Acids; D011453:Prostaglandins; D012694:Serine; C025984:15-hydroxy-5,8,11,13-eicosatetraenoic acid; D008715:Methionine; D011451:Prostaglandin-Endoperoxide Synthases; D001241:Aspirin