Alpha-dioxygenase that catalyzes the primary oxygenation step of a variety of 14-20 carbon fatty acids, containing up to three unsaturated bonds, into their corresponding 2R-hydroperoxides (PubMed:18760499, PubMed:10938370). Involved in the production of oxylipins that function in cell signaling, wound healing, and protection from infection (PubMed:18760499, PubMed:10938370). The alpha-oxidation pathway of fatty acids may play a role during plant developmental processes (PubMed:18760499). hexadecanoate + O2 = (2R)-2-hydroperoxyhexadecanoate dodecanoate + O2 = (2R)-2-hydroperoxydodecanoate Binds 1 heme b (iron(II)-protoporphyrin IX) group per subunit. Binds 1 calcium ion per subunit. Expressed in germinating seeds and then root seedlings up to 12 days after imbibition. Belongs to the peroxidase family.