. "Catalysis of the reaction: 4-hydroxyphenylacetate + NADH + H+ + O2 = 3,4-dihydroxyphenylacetate + NAD+ + H2O." . . "4-hydroxyphenylacetate,NADH:oxygen oxidoreductase (3-hydroxylating) activity" . "4 HPA 3-hydroxylase activity" . "4-hydroxyphenylacetate 3-hydroxylase activity" . "4-hydroxyphenylacetate 3-monooxygenase activity" . "p-hydroxyphenylacetate 3-hydroxylase activity" . "p-hydroxyphenylacetate hydroxylase activity" . . .