Biochemistry (Moscow)

, Volume 72, Issue 6, pp 631–639

Cyclooxygenase and peroxidase inactivation of prostaglandin-H-synthase during catalysis

Article

DOI: 10.1134/S0006297907060053

Cite this article as:
Tsaplina, L.A. & Vrzheshch, P.V. Biochemistry Moscow (2007) 72: 631. doi:10.1134/S0006297907060053

Abstract

Prostaglandin-H-synthase (PGHS) is a bifunctional enzyme catalyzing cyclooxygenase and peroxidase reactions and undergoing irreversible inactivation during catalysis. A new method for kinetic studies of both PGHS activities in the course of cyclooxygenase as well as peroxidase reactions and also preincubation with hydroperoxides is suggested. It is shown that peroxidase activity is retained after complete cyclooxygenase inactivation and cyclooxygenase activity is retained after complete peroxidase inactivation. Two-stage cyclooxygenase inactivation occurs on preincubation of PGHS with hydrogen peroxide. Studies on inactivation under various conditions indicate that chemical mechanisms of cyclooxygenase and per-oxidase inactivation are different. The data allow development of kinetic models.

Key words

prostaglandin-H-synthasecyclooxygenase activityperoxidase activityinactivationTMPDABTS

Abbreviations

AA

arachidonic acid

ABTS

2,2′-azino-di-3-ethyl-benzotiazoline-6-sulfonic acid

DEDTC

diethyldithiocarbamate

PGG2

prostaglandin G2

PGHS

prostaglandin-H-synthase

PPIX

protoporphyrin IX

TMPD

N,N,N′,N′-tetramethyl-p-phenylenediamine

Copyright information

© Pleiades Publishing, Ltd. 2007

Authors and Affiliations

  1. 1.Faculty of Bioengineering and BioinformaticsLomonosov Moscow State UniversityMoscowRussia
  2. 2.International Biotechnological CenterLomonosov Moscow State UniversityMoscowRussia