From lignins to tannins: Forty years of enzyme studies on the biosynthesis of phenolic compounds

In the early 1960s, enzyme studies began to replace previously prevalent 'feeding' experiments with labeled tracers to elucidate metabolic pathways in higher plants. This insights, particularly on the role of 'energy-rich' intermediates, were obtained by this advanced technique. Based on the author's own experience, principal findings and trends over the past 40+ years in the enzymology of plant phenolics (lignins, acyl amides and hydrolyzable tannins) are reported.