title: Disorder in milk proteins: structure, functional disorder, and biocidal potentials of lactoperoxidase.
abstract: This article continues a series of reviews on the abundance and roles of intrinsic disorder in milk proteins. Besides caseins, which are the major proteinaceous constituents of any milk that can be isolated by isoelectric precipitation, milk contains a set of soluble whey proteins, such as β-lactoglobulin, α-lactalbumin, serum albumin, immunoglobulins, lactoferrin, lactoperoxidase, glycomacropeptide, and proteose peptone (the last two are soluble casein derivatives). Lactoferrin and lactoperoxidase (LPO) are known to possess prominent biocidal activity, serving as efficient antibiotics and antiviral agents against a wide spectrum of bacteria, fungi, and viruses. LPO is a heme-containing peroxidase expressed as preproprotein. The mature protein has a single catalytic domain, structure of which is known for a protein isolated from several species. Functionally, LPO is a crucial component of the LPO system that includes LPO, hydrogen peroxide (H2O2), and thiocyanate (SCN(-)), being a well-studied, naturally occurring antimicrobial system in milk that is effective against many microorganisms and some viruses. Although various aspects of LPO structure and function are rather well studied and were subjects of several recent reviews, the abundance and potential functional roles of intrinsically disordered regions in this protein have never being addressed as of yet. The major goal of this article is to fill this gap and to show how intrinsic disorder is encoded in the amino acid sequence of LPO, and how intrinsic disorder is related to functions of this important milk protein.
authors.forename: Hussein A
authors.initials: HA
authors.lastname: Almehdar
authors.forename: Esmail M
authors.initials: EM
authors.lastname: El-Fakharany
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Uversky
authors.affiliation: Department of Biological Science, Faculty of Science, King Abdulaziz University, Jeddah, PO Box 80203, Jeddah 21589, Saudi Arabia. vuversky@health.usf.edu.
authors.forename: Elrashdy M
authors.initials: EM
authors.lastname: Redwan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D064267:Intrinsically Disordered Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D007784:Lactoperoxidase / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D008894:Milk Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D008969:Molecular Sequence Data
chemical_list: D000890:Anti-Infective Agents; D064267:Intrinsically Disordered Proteins; D008894:Milk Proteins; D007784:Lactoperoxidase