The shikimate pathway. Part V. Chorismic acid and chorismate mutase

Abstract

The chemistry of the biochemical intermediate chorismic acid {trans-3-[(1-carboxyvinyl)oxy]-4-hydroxycyclohexa-1,5-diene-1-carboxylic acid}(1) is discussed, including the formation of the fused pyrazoline (6) with diazomethane, the dihydro-derivatives (8) and (9) with di-imide, and the epoxide (10). The mode of action of the enzyme chorismate mutase (EC 1.3.1.12), which transforms chorismic acid into prephenic acid (3), is of importance in relation to general theories of enzyme action. The reaction is the sole example in primary metabolism of an enzyme-catalysed ortho-Claisen rearrangement, and attempts to elucidate the stereochemical features of this molecular reorganisation are outlined.