Retinol Binding Protein from human urine

Retinol Binding Protein (RBP) is a member of lipocalin superfamily. The normal concentration of RBP in serum is 40 to 50 μg/mL and has a molecular weight of 21 kDa. It has a turnover rate of 4 to 24 h. RBP is produced in the liver in response to retinol binding trigger. It is also produced in kidney, sertoli cells of testis. RBP contains a single globular domain and a highly conserved N-terminal region. It has eight antiparallel β sheets in the centre which binds retinol. In human chromosome, the gene encoding RBP is localised at 3q23.

Retinol Binding Protein from human urine has been used:

• as one of the protein in microinjecting mesencephalic cavity of chicken eggs to monitor embryonic cerebrospinal fluid/embryonic serum protein transfer
• as an additive in basal medium for RNA transfection experiments
• in the antibody-derivatized affinity pipettes preparation for the capture of affinity proteins

Inflammation induced by lipopolysaccharide (LPS) exposure caused a reduction in the level of retinol binding protein produced by the liver.

Retinol Binding Protein (RBP) is a specific protein for the transport of vitamin A. The apo-RBP, formed after delivering retinol to the tissues is catabolized by the kidney. The plasma concentration of RBP is less in diabetes mellitus patients. RBP binds to the carrier protein transerythrin, to prevent its loss during glomerular filtration. RBP is implicated in initial neurogenesis and neuroepithelial cell proliferation. RBP is responsible for blepharophimosis syndrome (BPES).

Solution in 10 mM sodium phosphate, pH 7.4, 150 mM NaCl, and 0.05% NaN₃