A vanadium‐51 NMR study of the binding of vanadate and peroxovanadate to proteins

51 V quadrupolar central transition NMR spectra of buffered (pH 7.6–8.0) solutions of bovine apo‐transferrin (Tf) and bovine prostatic acid phosphatase (Pp) treated with vanadate show normal features (chemical shifts between −515 and −542 ppm) corresponding to the complexation of VO 2 + to the Tf binding site and the Pp active centre, respectively. Addition of H 2 O 2 leads to the temporary formation of complexed VO(O 2 ) + (δ ≈ −595). Vanadate‐dependent bromoperoxidase from the alga Ascophyllum nodosum exhibits an unusually high shielding both for the native (δ = −931) and the peroxo form (δ = −1135) of the enzyme. A resonance at −471 ppm is traced back to an inactive form with oxovanadium(V) in a trigonal‐bipyramidal array. Copyright © 2004 John Wiley & Sons, Ltd.