Characterization of rat spleen prostaglandin H d-isomerase as a sigma-class GSH transferase

Abstract

The prostaglandin H D-isomerase of rat immune accessory cells has been purified from spleen by a simple procedure, and its high specificity and activity [Urade, Fujimoto, Ujihara and Hayaishi (1987) J. Biol. Chem. 262, 3820-3825] have been confirmed in an assay coupled to prostaglandin H synthase. The enzyme also decreases the formation of 12[S]-hydroxy-5,8,10-heptadecatrienoic acid formed by the synthase in the presence of GSH and increases the overall rate of arachidonate oxidation. A partial amino acid sequence shows a strong relationship to GSH transferases of parasitic helminths and molluscs, indicating that it is the first example of a vertebrate sigma-class GSH transferase, and suggesting that certain helminth GSH transferases may be involved in prostaglandin synthesis.