Scheme 2
From: A colorimetric assay to rapidly determine the activities of lytic polysaccharide monooxygenases
Schematic diagram of the colorimetric assay of type-1 (C1) LPMO enzyme activity. After LPMO treatment, the surface oxidized polysaccharide was precipitated by centrifugation, and soluble moieties including enzyme, metal ions and reducing agent were removed as supernatant. Polysaccharides were washed with HEPES buffer before Ni2+ was added to the polysaccharide surface carboxylates for ionic adsorption. A change in Ni2+ concentration in the supernatant was measured using pyrocatechol violet (PV) as an indicator. Absorbance was recorded and converted to numbers of carboxylate group introduced by the LPMO