Spin labeling
The spin label can be attached to the target by covalent bonds or by non-covalent gravitational forces involved in the interactions of enzymes and coenzymes, enzymes and substrates, antibodies and haptens, and membranes and steroids. The spin labeling method has been widely used to study the conformation of biopolymers, the structure of the active site of enzymes, the structure of liposomes and biofilms, and the application of immunoassays.