Probable calcium-binding peroxygenase. May be involved in the degradation of storage lipid in oil bodies, in abiotic stress-related signaling pathway and in drought tolerance through stomatal control under water deficit conditions. RH + ROOH = ROH + ROH. Binds 1 heme b (iron(II)-protoporphyrin IX) group. Homodimer. Expressed in cotyledons, hypocotyls, leaves, shoots, flowers, stems, siliques, hydatodes, trichome bases and guard cells. Not detected in roots, mature brown siliques or mature dry seeds. Expressed in the first days following fertilization, but not in mature seeds. Up-regulated by drought, abscisic acid, osmotic stress, salicylic acid, wounding and pathogens, but very low induction by jasmonic acid. Transmembrane regions are predicted by sequence analysis tools, but these regions probably constitute hydrophobic domains associated to phospholipids. The proline-knot motif (113-122) may be involved in targeting to lipid bodies. Phosphorylated. Increased phosphorylation upon stress. Increased drought and salt stress sensitivity. Delayed seed germination and reduced cotyledon opening and greening in presence of abscisic acid. The N-terminus is facing into the microsomal vesicles. Belongs to the caleosin family.