1.3.1.24 bilirubin + NAD(P)+ = biliverdin + NAD(P)H + H+ - - 1.3.1.24 bilirubin + NAD(P)+ = biliverdin + NAD(P)H + H+ catalysis via hydride transfer from NADH 656502 1.3.1.24 bilirubin + NAD(P)+ = biliverdin + NAD(P)H + H+ induced fit docking is emplyed to study the substrate binding modes to hBVR-A of biliverdin-IXalpha and four analogues. Substrate binding modes are examined further by performing molecular dynamics (MD) simulations followed by molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) calculations. On the basis of our calculations, the energetically preferred pathway consists of an initial protonation of the pyrrolic nitrogen on the biliverdin substrate followed by hydride transfer to yield the reduction product 725786