3-Carboxyumbelliferyl β-D-galactopyranoside releases free 3-carboxyumbelliferone upon bet-galactosidase enzyme activity. 3-caboxyumbelliferone has the following fluorescent activity: λex = 386, λem 445 nm, ε = 32K. In acidic conditions (below pKa 7.8) the absorption shifts to lower wavelengths (235-340 nm) and fluorescence intensity decreases.Water soluble Blue Fluorogenic enzyme substrate 3-Carboxyumbelliferyl β-D-galactopyranoside releases free 3-carboxyumbelliferone upon bet-galactosidase enzyme activity. 3-caboxyumbelliferone has the following fluorescent activity: λex = 386, λem 445 nm, ε = 32K. In acidic conditions (below pKa 7.8) the absorption shifts to lower wavelengths (235-340 nm) and fluorescence intensity decreases. Water soluble Blue Fluorogenic enzyme substrate