Figure 1.

Simplified Scheme of the Phenylpropanoid-Lignin Biosynthetic Pathway, Illustrating Three P450 Enzyme-Catalyzed Hydroxylation Reactions in Monolignol Biosynthesis.

ALDH, aldehyde dehydrogenase; CAD, (hydroxy)cinnamyl alcohol dehydrogenase; CCoAOMT, caffeoyl CoA 3-O-methyltransferase; CCR, cinnamoyl CoA reductase; 4CL, 4-hydroxycinnamoyl CoA ligase; COMT, caffeic acid/5-hydroxyferulic acid 3/5-O-methyltransferase; CSE, caffeoyl shikimate esterase; HCT, hydroxycinnamoyl CoA:shikimate/quinate hydroxycinnamoyltransferase; PAL, phenylalanine ammonia lyase; PTAL, phenylalanine and tyrosine ammonia lyase; SGT, sinapate glucosyltransferase; SMT, sinapoylglucose:malate sinapoyltransferase. Gray letters and arrows indicate that the pathway occurs in grass.