On the Characterization of Prostaglandin E 2 9-Keto Reductase from Aorta and Regional Differences in Its Activity

Abstract

Summary

Evidence is presented for the presence of a prostaglandin E₂ 9-keto reductase activity in the soluble fraction of the pigeon aorta. The enzyme reaction was stimulated by NADPH when 107,000g (1 h) supernatant was used as the enzyme source. Surprisingly, the enzyme activity exhibited two pH optimums (pH 4 and 7.4, respectively), in contrast to other tissues where only an optimum pH 7.4 was found. In the atherosclerotic portion of the aorta, the enzyme activity at pH 7.4 was reduced while the activity at pH 4 was enhanced.