title: Enzymatic dtermination of pyridoxal 5'-phosphate with gamma-cyanoaminobutyric acid aposynthase.
abstract: A rapid alternative method is presented for the determination of pyridoxal 5'-phosphate (pyridoxal-P). The method involves the colorimetric analysis of thiocyanate liberated from S-cyanohomocysteine (Hcy (CN)) in the presence of cyanide when catalyzed by the pyridoxal-P dependent enzyme, gamma-cyano-alpha-aminobutyric acid (gamma-CNabu)-synthase (Hcy (CN) thiocyano-lyase [adding CN]). The rate of formation of thiocyanate is determined by the increase in absorbance at 470 nm on treatment of the enzymatic reaction mixture with FeCl3.
mesh_terms: D001051:Apoenzymes / Q000032:analysis*; D001059:Apoproteins / Q000032:analysis*; D002151:Calorimetry; D003486:Cyanides; D006710:Homocysteine / Q000031:analogs & derivatives / Q000378:metabolism; D007202:Indicators and Reagents; D008190:Lyases / Q000032:analysis*; D011732:Pyridoxal Phosphate / Q000032:analysis*; D013861:Thiocyanates / Q000032:analysis / Q000378:metabolism
chemical_list: D001051:Apoenzymes; D001059:Apoproteins; D003486:Cyanides; D007202:Indicators and Reagents; D013861:Thiocyanates; D006710:Homocysteine; D011732:Pyridoxal Phosphate; D008190:Lyases