Retinol-binding protein
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 used to assess vitamin A deficiency as it binds 1:1 to retinol. RBP is classified according to its site of activity. Plasma RBP (PRBP) carries retinol in blood while cellular RBP (CRBP) carries retinol in the cell.
Plasma RBP (PRBP)
1rbp]], 1jyd - hRBP – human 1jyj]] - hRBP (mutant) 1aqb]] - RBP – pig
Cellular RBP (CRBP)
1jbh]], 1kgl, 1mx7 - rRBP I – NMR
1b4m]] - rRBP II – rat – NMR
2rcq]] - hRBP II
1ggl]] - hRBP III
1lpj]] - hRBP IV
1kqx – ZeRBP – zebrafish
Plasma RBP complex
3bsz]] - hRBP II + transthyretin + antibody + retinol
3fmz]] - hRBP IV + non-retinoid ligand
2wq9]] - hRBP IV + oleate
2wq9]] - hRBP IV + linoleate
2wqa]] - hRBP IV + transthyretin + oleate
1iiu]] - RBP + retinol – chicken
1kt3]], 1kt4, 1kt5, 1kt6, 1kt7 - RBP + retinol – bovine
Cellular RBP complex
1mx8]] - rRBP I + retinol – NMR
1eii]] - rRBP II + retinol – NMR
2rct]] - hRBP II + retinol
1kqw]] - ZeRBP + retinol