Hydroxylase involved in the oxidation of the plant hormone jasmonoyl-L-isoleucine (JA-Ile), a bioactive phytohormone of the jasmonate-mediated signaling pathway. Converts JA-Ile to 12-hydroxy-JA-Ile (PubMed:21576464, PubMed:21849397, PubMed:22215670). Exerts negative feedback control on JA-Ile levels and plays a key role in attenuation of jasmonate responses. Negatively regulates the expression of wound-induced genes TIFY11A/JAZ5, TIFY5A/JAZ8 and TIFY5A/JAZ10 (PubMed:21576464). Catalyzes the hydroxylation of jasmonoyl-L-valine (JA-Val), jasmonoyl-L-leucine (JA-Leu) and jasmonoyl-L-phenylalanine (JA-Phe) in vitro. Converts JA-Val, JA-Leu and JA-Phe to 12-hydroxy-JA-Val, 12-hydroxy-JA-Leu and 12-hydroxy-JA-Phe, respectively (PubMed:24467969). a jasmonyl-L-amino acid + O2 + reduced [NADPH--hemoprotein reductase] = a 12-hydroxyjasmonyl-L-alpha-amino acid + H(+) + H2O + oxidized [NADPH--hemoprotein reductase] H(+) + L-isoleucine-(+)-7-isojasmonate + NADPH + O2 = H2O + L-isoleucine-(+)-12-hydroxy-7-isojasmonate + NADP(+) a jasmonyl-L-isoleucinate + H(+) + NADPH + O2 = H2O + L-isoleucine-12-hydroxyjasmonate + NADP(+) Induced by wounding. No visible phenotype under normal growth conditions, but mutant plants accumulate high amounts of JA-Ile and have strongly reduced levels of 12-hydroxy-JA-Ile in response to wounding. Plants over-expressing CAP94B3 are deficient in jasmonate perception. Belongs to the cytochrome P450 family.