Lactoperoxidase: Properties, Functions, and Potential Applications

Lactoperoxidase (LPO) (E.C. 1.11.1.7) is a member of the superfamily of mammalian heme peroxidases that is isolated from milk, and it is the first enzyme announced to be found in milk. In addition to milk, LPO is also found in saliva, tears, and airways (airway goblet cells and submucosal glands). It contributes significantly to the self-defense of the mammal body. It catalyzes the oxidation of certain molecules such as thiocyanate (SCN^-), I^-, and Br^- in the presence of hydrogen peroxide (H₂O₂). This reaction leads to the formation of antimicrobial products that have a great antimicrobial spectrum, including antibacterial, antiviral, and antifungal activity, especially hypothiocyanite (OSCN^-) and hypoiodite (OI^-), which are coming into prominence via their high antimicrobial activity. The lactoperoxidase system (LPOS) is the system consisting of LPO, H₂O₂, and SCN^-. LPO has a great potential to be used in various areas such as preservation and shelf-life elongation of milk; milk products; meat; meat products; plants, including fruits and vegetables; and oral care, diagnosis, immunomodulation, and treatment of nephrotoxicity. The LPO gene, along with LPO itself, is important for animals. In the absence of the LPO gene, there is an increase in the frequency of diverse diseases, including inflammation, tumor formation, and obesity. In this review, we mentioned general information about the enzyme LPO and its potential. Chemical properties and other features of other components of the LPOS, H₂O₂, and SCN^- were also touched on the review. To offer readers a comprehensive understanding of the enzyme's biological significance and research progress over time, both recent and older studies have been used together. Lastly, we discussed potential applications of LPO in different areas and left future remarks in the light of recent studies.