title: Surface plasmon resonance studies and biochemical evaluation of a potent peptide inhibitor against cyclooxygenase-2 as an anti-inflammatory agent.
abstract: Cyclooxygenase (COX) is a key enzyme in the biosynthetic pathway leading to the formation of prostaglandins, which are mediators of inflammation [D.L. Dewitt, W.L. Smith, Primary structure of prostaglandin G/H synthase from sheep vesicular gland determined from the complementary DNA sequence, Proc. Natl. Acad. Sci. USA 85 (1988) 1412-1416, 1]. It exists mainly in two isoforms COX-1 and COX-2 [A. Raz, A. Wyche, N. Siegel, P. Needleman, Regulation of fibroblast cyclooxygenase synthesis by interleukin-1, J. Biol. Chem. 263 (1988) 3022-3028, 2]. The conventional non-steroidal anti-inflammatory drugs (NSAIDs) have adverse gastrointestinal side-effects, because they inhibit both isoforms [T.D. Warner, F. Guiliano, I. Vojnovic, A. Bukasa, J.A. Mitchell, J.P. Vane, Nonsteroid drug selectivities for cyclo-oxygenase-1 rather than cyclo-oxygenase-2 are associated with human gastrointestinal toxicity: a full in vitro analysis, Proc. Natl. Acad. Sci. USA 96 (1999) 7563-7568, 3; L.J. Marnett, A.S. Kalgutkar, Cyclooxygenase 2 inhibitors: discovery, selectivity and the future, Trends Pharmacol. Sci. 20 (1999) 465-469, 4; J.R. Vane, NSAIDs, Cox-2 inhibitors, and the gut, Lancet 346 (1995) 1105-1106, 5]. Therefore drugs which selectively inhibit COX-2, known as coxibs were developed. Recent reports on the harmful cardiovascular and renovascular side-effects of the anti-inflammatory drugs have led to the quest for a novel class of COX-2 selective inhibitors. Keeping this in mind, we have used the X-ray crystal structures of the complexes of the COX-1 and COX-2 with the known inhibitors for a rational, structure based approach to design a small peptide, which is potent inhibitor for COX-2. The peptides have been checked experimentally by in-vitro kinetic studies using surface plasmon resonance (SPR) and other biochemical methods. We have identified a tripeptide inhibitor which is a potential lead for a new class of COX-2 inhibitor. The dissociation constant (K(D)) determined for COX-2 with peptide WCS is 1.90x10(-10)M, the kinetic constant (K(i)) determined by spectrophotometry is 4.85x10(-9)M and the IC(50) value is 1.5x10(-8)M by ELISA test.
authors.affiliation: Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
authors.forename: Rishi K
authors.initials: RK
authors.lastname: Somvanshi
authors.forename: Ashwini
authors.initials: A
authors.lastname: Kumar
authors.forename: Shashi
authors.initials: S
authors.lastname: Kant
authors.forename: Deepti
authors.initials: D
authors.lastname: Gupta
authors.forename: S Bhaskar
authors.initials: SB
authors.lastname: Singh
authors.forename: Utpal
authors.initials: U
authors.lastname: Das
authors.forename: Alagiri
authors.initials: A
authors.lastname: Srinivasan
authors.forename: Tej P
authors.initials: TP
authors.lastname: Singh
authors.forename: Sharmistha
authors.initials: S
authors.lastname: Dey
mesh_terms: D051546:Cyclooxygenase 2 / Q000737:chemistry / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D015195:Drug Design; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects; D020349:Surface Plasmon Resonance
chemical_list: D052246:Cyclooxygenase 2 Inhibitors; D008565:Membrane Proteins; D009842:Oligopeptides; C522909:tryptophyl-cysteinyl-serine; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human