BLVRB
Description
The BLVRB (biliverdin reductase B) is a protein-coding gene located on chromosome 19.
Biliverdin reductase B is a protein that in humans is encoded by the BLVRB gene. The BLVRB gene was localized to chromosome 19, the specific region being 19q13.13 to q13.2; this was done using fluorescence in situ hybridization. BLVRB encodes a protein that is a 206-residue monomeric enzyme. The structure of BVR-B has a single-domain architecture consisting of a central parallel beta-sheet with alpha-helices on either side. This characteristic dinucleotide binding fold comprises, in this case, a seven-stranded parallel beta-sheet further extended by an antiparallel strand. In addition to the seven long strands of the main pleated sheet, a short parallel beta-sheet (strands 6a and 6c) is formed within the loop joining strand 6 and alpha-helix F. The central beta-sheet and the two groups of helices are held together mainly through hydrophobic interactions. One group of helices is made up of alpha-helices C, D, and E. The second group is composed of alpha-helices A and F and includes a short 310-helix between strands beta2 and beta3, in contrast to typical dinucleotide binding proteins in which a regular alpha-helix flanks these beta-strands. The most flexible loop in the structure corresponds to loop 120, between strand 5 and alpha-helix E, which contains residues with the highest main chain B-factors, with the exception of the N-terminal region. The final step in heme metabolism in mammals is catalyzed by the cytosolic biliverdin reductase enzymes A and B (EC 1.3.1.24). From a functional standpoint, it has been hypothesized that BLRVB is identical to flavin reductase (FR), an enzyme that catalyzes the NADPH-dependent reduction of FMN and Methylene Blue and, in the presence of redox couplers, the reduction of methaemoglobin.
BLVRB is a broad specificity oxidoreductase that catalyzes the NADPH-dependent reduction of various flavins, including riboflavin, FAD, FMN, biliverdins, methemoglobin, and PQQ (pyrroloquinoline quinone). It contributes to heme catabolism and metabolizes linear tetrapyrroles. BLVRB can also reduce complexed Fe(3+) iron to Fe(2+) in the presence of FMN and NADPH. In the liver, it converts biliverdin to bilirubin.
BLVRB is also known as BVRB, FLR, HEL-S-10, SDR43U1.
