Fluid Solution and Solid-State Electron Nuclear Double Resonance Studies of Flavin Model Compounds and Flavoenzymes

Article abstract of DOI:10.1021/ja00315a048

Partially deuterated and various substituted flavin and thiaflavin model compounds have been synthesized.For the first time, high-resolution H, D, and 14N ENDOR and TRIPLE resonance experiments in fluid solution have been performed on the paramagnetic derivatives of these compounds.Additionally, valuable information has been obtained about hyperfine anisotropies and molecular structures from ENDOR in rigid matrices.Solid matrix ENDOR studies of native flavoenzymes, namely, "Old Yellow Enzyme" (NADPH dehydrogenase), two flavodoxins, and a methanol oxidase are reported.The ENDOR matrix signals of the various flavoproteins are different in intensity, suggesting that the microenvironments are remarkably different.Applicabilities and limitations of the ENDOR technique in the studies of flavins and flavoenzymes are discussed.