HAP-01, the first chromogenic substrate for acid protease

The first chromogenic substrate for Aspergillus oryzae acid protease, 'HAP-01', was successfully developed after evaluating the substrate specificity of the enzyme. Furthermore, with HAP-01, digestion-triggered chromophore release was employed as a novel chromogenic technique. HAP-01 was developed as an activity-based probe for A. oryzae acid protease important for production of sake , a Japanese rice wine.