3-phenylpropionate/cinnamic acid dioxygenase ferredoxin--NAD(+) reductase component; Part of the multicomponent 3-phenylpropionate dioxygenase, that converts 3-phenylpropionic acid (PP) and cinnamic acid (CI) into 3-phenylpropionate-dihydrodiol (PP- dihydrodiol) and cinnamic acid-dihydrodiol (CI-dihydrodiol), respectively (By similarity) (400 aa)