View source for Retinol-binding protein

<StructureSection load='' size='400' side='right' scene='48/488393/Cv/1' caption='Human cellular retinol-binding protein II complex with retinol, sulfate and tartarate, [[2rct]]'>
== Function ==
'''Retinol-binding protein''' (RBP) are carrier proteins which bind retinol (vitamin A alcohol).  Human RBP4 is the carrier of retinol in the blood.  It delivers retinol from the liver to the peripheral tissues.  RBP also functions in regulation, metabolism and activities of retinoids.  Retinol is being protected from oxidation and becomes soluble when bound to RBP.  RBP is classified according to its site of activity.  '''Plasma RBP''' (PRBP) carries retinol in blood<ref>PMID:6994566</ref> while '''cellular RBP''' (CRBP) carries retinol in the cell<ref>PMID:2825608</ref>.
*'''Interphotoreceptor retinoid-binding protein''' (iRBP) is involved in the regeneration of rhodopsin in the visual cycle<ref>PMID:8318167</ref>.

== Relevance ==
RBP is used to assess vitamin A deficiency as it binds 1:1 to retinol<ref>PMID:10953676</ref>.  RBP IV is used as biomarker for renal dysfunction and cardiovascular disease in type II diabetes<ref>PMID:17875187</ref>.

== Structural highlights ==
<scene name='48/488393/Cv/7'>Retinol binds to cellular RBP II inside its internal cavity</scene><ref>PMID:18076076</ref>. <scene name='48/488393/Cv/8'>Active site</scene>. Water molecules are shown as red spheres.
==3D structures of retinol-binding protein==
[[Retinol-binding protein 3D structures]]

</StructureSection>

== References ==
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