Enzyme involved in the ethylene biosynthesis. 1-aminocyclopropane-1-carboxylate + L-ascorbate + O2 = CO2 + ethene + 2 H2O + hydrogen cyanide + L-dehydroascorbate Binds 1 Fe(2+) ion per subunit. Alkene biosynthesis; ethylene biosynthesis via S-adenosyl-L-methionine; ethylene from S-adenosyl-L-methionine: step 2/2. Belongs to the iron/ascorbate-dependent oxidoreductase family.