Lactopontin: A Bioactive milk protein and its health benefits

Milk is a natural source of nutrients and bioactive proteins necessary for the health and growth of infants. The milk proteins possess bio-functional activities with considerable physiology for health and protection against infection and disease. Milk contains different types of bioactive proteins like lactoferrin, lactoperoxidase, immunoglobulins, mucin-1, lysozyme, lactophorin and several other milk proteins derived bioactive components. Among the many different components likelipids, lactose, human milk oligosaccharides, proteins are crucial nutritional and bioactive molecular factors in human milk. In recent years, osteopontin (OPN) in milk are also known as lactopontin (LPN) (Shiraga et al., 1992: Senger et al., 1989), has concerned that much attention. Lactopontin is one of the important minor bioactive milk protein. Lactopontin is also known as early T cell activation gene-1, uropontin, nephropontin, urinary stone protein, osteopontin, bone sialoprotein, and secretory phosphoprotein but it is commonly named as osteopontin. OPN was first identified in bone tissue as a bone matrix protein (Brown  et al., 1992; Schack , Schack et al.,2009) and has a various physiological fluids of human, rat, mouse, pig, cow, buffalo and rabbit but milk is the its richest source. LPN is classified as matricellular protein of interleukin family. Lactopontin is recognized as an early acting cytokine regulating the intensity and duration of immune response by exerting a variety of effects on lymphocytes and other immune cells.