ESR probing of macromolecules: Spin-labeling of the active sites of the proteolytic serine enzymes

Spin-labeled fluorophosphonates react with serine proteinases and esterases in a manner analogous to the common active phosphate ester inhibitors. The reporter group properties of the spin-labeled inhibitors enable a comparative study of the micro structure of the active sites of these enzymes as well as a facile determination of rates of inhibition. The effect of various environmental perturbations on the conformation of these active sites has also been probed.