title: Calcium and 25-hydroxyvitamin D3 binding proteins in human placenta.
abstract: The placental translocation of calcium is a well-known process, but the underlying mechanisms remain unknown. Placental cytoplasmic proteins capable of binding calcium and the active metabolites of vitamin D3 were sought in these studies. Cytosol from full-term human placenta was prepared by ultracentrifugation of homogenates and tested for binding. Partial purification by column chromatography revealed the presence of two discrete proteins which bound specifically 45Ca and 3H-25-hydroxyvitamin D3 and having approximate molecular weights of 12,000 and 67,000, respectively. These placental proteins may be intermediaries in the process of placental calcium translocation.
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002762:Cholecalciferol / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D005260:Female; D006801:Humans; D006887:Hydroxycholecalciferols / Q000378:metabolism; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011485:Protein Binding
chemical_list: D006887:Hydroxycholecalciferols; D002762:Cholecalciferol; D002118:Calcium