3d image of stercobilin skeletal formula

stercobilin tetrapyrrolic bile pigment heme catabolism urobilin fecal pollution rivers erythrocytes macrophages biliverdin bilirubin plasma protein albumin bilirubin diglucuronide urobilinogen stercobilinogen obstructive jaundice brown pigment gallstones cholelithiasis biliary tract metabolite metabolism biosynthesis cycle mechanism pathway path biosynthetic intermediate biogenesis substrate precursor synthesis derivative bioprecursor metabolic enzyme endogenous molecule molecular formula skeletal structural structure 3d