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FLASH GENE
Symbol HP contributors: mct/npt - updated : 17-12-2009
HGNC name haptoglobin
HGNC id 5141
PROTEIN
PHYSICAL PROPERTIES
STRUCTURE
motifs/domains
  • N-terminal AA sequence has striking similarities to the light chain of human gamma-globulins (Tripathi 2009)
  • a short consensus repeat
  • a peptidase S1 domain
  • growth factor-like repeats
  • 2 sushi structures (see F13B, SRCP1)
  • only the beta-chain of haptoglobin is involved in receptor recognition (Cd163) (Nielsen 2007)
    • secondary structure
  • mature HPs are heterodimeric plasma glycoproteins composed of alpha- and beta-polypeptide chains that are covalently associated by disulfide bonds and in which only the beta-chain is glycosylated (Tripathi 2009)
    • conjugated GlycoP
    mono polymer heteromer , tetramer
    isoforms Precursor including alpha (1 or 2,84/143AAs) and beta chains (244AAs)
    HOMOLOGY
    interspecies homolog to murine Hp
    Homologene
    FAMILY
  • peptidase S1 family
    • CATEGORY transport carrier
    SUBCELLULAR LOCALIZATION extracellular
    basic FUNCTION
  • combines with free plasma hemoglobin, preventing loss of iron through the kidneys and protecting the kidneys from damage by hemoglobin, while making the hemoglobin accessible to degradative enzymes
  • binds the apolipoprotein (Apo) A-I domain, which is involved in stimulating the enzyme lecithin-cholesterol acyltransferase (LCAT) for cholesterol esterification (Salvatore 2009)
  • protects Hb when oxidatively challenged with H(2)O(2) preserving CD163-mediated Hb clearance under oxidative stress conditions (Buehler 2009)
    • CELLULAR PROCESS
    PHYSIOLOGICAL PROCESS
    PATHWAY
    metabolism
    signaling
    a component
  • heterotetramer alpha 2/beta 2 complexing with free oxyhemoglobin to be removed and degraded in liver
  • dimer of alphabeta-chains covalently linked by a disulphide bond between the Cys15 residue of each alpha-chain (Polticelli 2008)
    • INTERACTION
    DNA
    RNA
    small molecule
    protein
  • binding free oxyhemoglobin
    • cell & other
    REGULATION
    ASSOCIATED DISORDERS
    corresponding disease(s) HP
    Susceptibility
    Variant & Polymorphism
    Candidate gene
    Marker
    Therapy target
    ANIMAL & CELL MODELS