Second-coordination-sphere effects increase the catalytic efficiency of an extended model for Fe(III)M(II) purple acid phosphatases.

Herein we describe the synthesis of a new heterodinuclear Fe(III)Cu(II) model complex for the active site of purple acid phosphatases and its binding to a polyamine chain, a model for the amino acid residues around the active site. The properties of these systems and their catalytic activity in the hydrolysis of bis(2,4-dinitrophenyl)phosphate are compared, and conclusions regarding the effects of the second coordination sphere are drawn. The positive effect of the polymeric chain on DNA hydrolysis is also described and discussed.