Heme-containing oxidoreductase which catalyzes the conversion of thiocyanate (SCN(-)) into antimicrobial agent hypothiocyanous acid (OSCN(-)) in the presence of hydrogen peroxide (H2O2) (By similarity). Also involved in the conversion of iodide (I(-)) into hypoiodite (IO(-)) in the presence of H2O2 (By similarity). Responsible for the inactivation of a wide range of micro-organisms and hence, important component of defense mechanism . Shows antibacterial properties against Pseudomonas aeruginosa . The lactoperoxidase-SCN(-)-H2O2 system shows antibacterial properties against Burkholderia cepacia and Haemophilus influenzae in vitro . Present in mammary and salivary gland secretions and may contribute to airway host defense against infection . May contribute to maintaining an appropriate H2O2 cellular level, therefore protecting cells from H2O2-caused injuries and inflammation (By similarity).
Subcellular locations: Secreted, Cytoplasm
Mammary gland, milk and salivary gland. Found in bronchial submucosal glands.