Human PAI-1 NBD labeled at the scissile bond of the reactive loop

Human PAI-1 NBD labeled at the scissile bond of the reactive loop

P1'-NBD PAI-1 was created by mutagenesis of the P1' serine residue (Ser347) at the P1-P1' scissile bond to cysteine. This then provides a free thiol group for NBD labeling, a fluorescent probe highly sensitive to changes in solvation and hydrophobic environment. The fluorescence emission of P1'-NBD PAI-1 is quenched upon cleavage of the reactive center loop by a target proteinase.