![]() ![]() The enzyme is sensitive to acetaminophen and highly expressed in the central nervous system, suggesting that inhibiting COX-3 may represent an important mechanism for controlling the synthesis of prostanoids mediating pain and fever. Ī third COX isoform, named COX-3, has recently been characterized in dogs. COX-2 expression can be induced in response to growth factors, cytokines, proinflammatory stimuli, carcinogens, tumor promoting phorbol esters. ĬOX-2 is found in brain, kidney and endothelial cells. 8,13 It is involved in several inflammatory and pathological conditions. The COX-2 gene is about 8 kb long with 10 exons and it is transcribed as 4.6, 4.0 and 2.8 kb mRNAs variants. It is involved in several physiological functions like maintainance of homeostasis (gastric and renal integrity) and normal production of PG. ![]() The COX-1 gene is ,22 kilobases (kb) in length, contains 11 exons, maps to human chromosome 9q32-q33.3, and is transcribed as a 2.8 kb mRNA. The primary structure of COX-1 was first characterized in sheep and subsequently in a number of species (Merlie et al., 1988 DeWitt and Smith, 1988 Smith et al., 2000). COX-1 and -2 share the same substrates, produce the same products, and catalyze the same reaction using identical catalytic mechanisms. COXs catalyze the conversion of AA to PGs and thromboxanes, which trigger as autocrine and paracrine chemical messengers in many physiological and pathophysiological responses. The COXs exist in two isoforms, a constitutive form (COX-1) and an inducible form (COX-2), and a COX-1 splice variant termed as COX-3 has been reported. Peroxidase activity is involved in reduction of PGG 2 to PGH 2. Cyclooxygenation 2.peroxidation.Ĭyclooxygenase activity is responsible for bisoxygenation of arachidonic acid to PGG 2.i.e., COX cyclizes and adds 2 molecules of oxygen to AA for formation of cyclo hydroperoxide PGG 2. ĬOX is involved in two pathways or two catalytic activities. It is also referred as prostaglandin synthase, prostaglandin endoperoxidase or prostaglandin G/H synthase. ĬOX is an enzyme that is responsible for formation of different forms of prostaglandins. There are different types of prostaglandins like PGD 2, PGE 2, PGF 2, PGI 2. They play a very prominent role in reproductive biology like ovulation, endometrial physiology, proliferation of endometrial glands and menstruation and pathological conditions like dysmenorrhoea, carcinoma, endometriosis, menorrhagia. Arachidonic acid is derived from membrane phospholipids catalyzed by PLA 2. Prostaglandins are potent bioactive lipid messengers synthesized from arachidonic acid mediated by enzyme COX. How to cite this article: SR Silpa Prostaglandins and its Types PharmaTutor 2014 2(5) 31-37 ![]()
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