Enzyme involved in the ethylene biosynthesis. Required to mediate the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germination via endosperm rupture. May promote stem elongation by maximizing the extensibility cells, possibly by activating ethylene biosynthesis, in response to very-long-chain fatty acids (VLCFAs C20:0 to C30:0). 1-aminocyclopropane-1-carboxylate + L-ascorbate + O2 = CO2 + ethene + 2 H2O + hydrogen cyanide + L-dehydroascorbate Binds 1 Fe(2+) ion per subunit. Can also bind Cu(2+) ions. Alkene biosynthesis; ethylene biosynthesis via S-adenosyl-L-methionine; ethylene from S-adenosyl-L-methionine: step 2/2. Expressed in vegetative tissues. Constitutively expressed in leaves and blades. In ethylene exposed etiolated seedlings, localized in cells at the outer side of the exaggerated hook in an ethylene-dependent manner and following an ethylene sensitive pattern. Also detected in the root tip when treated by ethylene. Upon iron deprivation. Induced by ethylene, particularly in root tips and hooks of ethiolated seedlings. Promoted by ozone O(3). Accumulates in response to very-long-chain fatty acids (VLCFAs C20:0 to C30:0). Induced in roots by nitric oxide (NO). Impaired in the 1-aminocyclopropane-1-carboxylic acid (ACC)-mediated reversion of the ABA-induced inhibition of seed germination. Belongs to the iron/ascorbate-dependent oxidoreductase family.