Order	Reaction ID	Reaction
1	R00050	caffeic acid + CoA + ATP → caffeoyl-CoA + AMP + PPi
2	R00051	caffeoyl-CoA + H<sub>2</sub>O → 3,4-dihydroxybenzaldehyde + acetyl-CoA
3	R00052	3,4-dihydroxybenzaldehyde + OH<sup>-</sup> → protocatechuic acid + 2H<sup>+</sup>