title: The synthesis of spin-label derivatives of NAD+ and its structural components and their binding to lactate dehydrogenase.
abstract: Spin-labelled derivatives of NAD+ and its structural components (i.e. adenosine, adenine, AMP, ADP and ADPR) have been synthesized. Their binding to pig heart lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) has been studied and dissociation constants have been determined. The spin-labelled derivatives of ADP and ADPR exhibit a tighter binding than the corresponding NAD+ derivative. This may be attributed to the repulsion of the positively charged nicotinamide ring by an histidine side chain in the active center of the enzyme.
mesh_terms: D000818:Animals; D001665:Binding Sites; D004578:Electron Spin Resonance Spectroscopy; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008722:Methods; D009206:Myocardium / Q000201:enzymology; D009243:NAD / Q000031:analogs & derivatives*; D011485:Protein Binding; D011487:Protein Conformation; D013113:Spin Labels; D013329:Structure-Activity Relationship; D013552:Swine
chemical_list: D013113:Spin Labels; D009243:NAD; D007770:L-Lactate Dehydrogenase