Chaperonin GroEL hydrolyses ortho -nitrophenyl β-galactoside.

We serendipitously found that chaperonin GroEL can hydrolyze ortho -nitrophenyl β-galactoside (ONPG), a well-known substrate of the enzyme β-galactosidase. The ONPG hydrolysis by GroEL follows typical enzyme kinetics. Our experiments and molecular docking studies suggest ONPG binding at the ATP binding site of GroEL.