Synthesis, characterization, kinetic parameters, and diagnostic application of a sensitive colorimetric substrate for β-galactosidase (2-chloro-4-nitrophenyl-β-D-galactopyranoside)

Article abstract of DOI:10.1006/bioo.1993.1024

The synthesis and characterization of 2-chloro-4-nitrophenyl β-D-galactopyranoside, an improved chromogenic substrate for β-galactosidase, is described. The important kinetic parameters (K_m, V_max and K_p) for this substrate were compared with those of other substrates. The diagnostic utility of this substrate in a digoxin liposome immunoassay is discussed. The new substrate offers at least four times the sensitivity enhancement as that with ortho-nitrophenyl β-D-galactopyranoside in the assays for β-galactosidase. This substrate should find use in enzyme immunoassays where βgalactosidase is used as a label. Copyright