Regioselective Hydrolysis of Human Serum Albumin by ZrIV-Substituted Polyoxotungstates at the Interface of Positively Charged Protein Surface Patches and Negatively Charged Amino Acid Residues

Complexes comprising the Lewis acidic Zr-IV metal and protein binding polyoxotungstate ligands of Lindqvist-, Keggin- and Wells-Dawson-type were found to region selectively hydrolyze human serum albumin at four distinct positions. Higher reactivities were found for structures with higher polyoxometalate charges and the cleavage positions were found in protein regions of mixed charge. Both findings suggest an electrostatic nature of the observed reactivity.