ABSTRACT
This chapter examines the general aspects of the application of electron paramagnetic resonance (EPR) and its related techniques such as electron nuclear double resonance and spin-echo spectroscopy to studies of copper proteins, and discusses their advantages and limitations. The absorption of microwave power by the sample at resonance changes the effective coupling of the cavity to the waveguide and hence the amount of microwave power reflected from the cavity. In the earliest EPR spectrometers, this change was observed directly by measuring the current through the crystal detector with a meter or an oscilloscope. The chapter discusses the development of the appropriate spin Hamiltonians and their application in the interpretation of the EPR spectra of copper proteins. In the rapid-freezing technique, reactants from two or three syringes are driven into a mixing tube by pressurized gas or a motor-driven cam system.
