Polyphenol oxidases exhibit promiscuous proteolytic activity

Tyrosinases are an industrially significant class of polyphenol oxidase. Here, two tyrosinases are shown to cleave a specific peptide bond in a carboxylesterase, yielding a truncated product with higher catalytic activity than the full-length enzyme

Synthesis, characterization, and POM-protein interactions of a Fe-substituted Krebs-type Sandwich-tungstoantimonate

The novel iron-substituted Krebs-type polyoxotungstate (C12N4H11)4Na2H5[(Fe(H2O)3)2((FeO2)0.5(WO2)0.5)2(β-SbW9O33)2] (Fe-1) has been synthesized using ortho-phenylenediamine (opda) as a precursor for the in situ formation of the counter cation 2,3-diaminophenazinium (C12N4H11)+ (2,3-DAP). Fe-1 has been thoroughly characterized in the solid state by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), IR spectroscopy, and elemental analysis as well as in solution by UV–Vis spectroscopy. The crystal structure of Fe-1 reveals π–π-interactions between the aromatic systems of the unconventional 2,3-DAP counter cation. POM-protein interaction studies using SDS-PAGE revealed a non-proteolytic behavior of Fe-1 towards Human Serum Albumin (HSA) as a model protein.© The Author(s) 201