Figure 1.

Possible pathways for phaselic acid biosynthesis in red clover. Proposed pathway enzymes for production of phaselic acid include Phe ammonia lyase (PAL), cinnamate 4-hydroxylase (C4H), 4-coumarate:CoA ligase (4CL), hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyl transferase (HCT-S), hydroxycinnamoyl-CoA:malate hydroxycinnamoyl transferase (HCT-M), and C3′H. Red clover gene products described here and elsewhere (Sullivan, 2009; Sullivan and Zarnowski, 2010) corresponding to the enzymatic activities are indicated in parentheses. The dashed line for 3′-hydroxylation of p-coumaroyl-malate indicates neither enzyme activity nor its corresponding gene has been detected in red clover. For simplicity, not all reactants and products are shown.