15-Hydroxy-9-oxoprosta-11,13-dienoic acid as the product of a prostaglandin isomerase

Abstract

The initial product of the interaction between prostaglandin A1 and the prostaglandin isomerase of cat blood plasma has been isolated. By ultraviolet spectroscopy and mass spectrometry and from stability and chromatographic studies, the structure of the compound has been established as 15-hydroxy-9-oxoprosta-11,13-dienoic acid, an allylic isomer of prostaglandin A1. The compound is unstable under mild alkaline conditions, isomerizing to prostaglandin B1. The biological significance of the enzymatic isomerization of prostaglandin A1 is discussed.

Keywords

• prostaglandins
• enzymatic isomerization
• keto–enol tautomerism
• conjugated diene