Biophysical chemistry studies biological systems. It is a relatively new branch of chemistry. It looks for explanations of the various phenomena in biological systems in terms of either the molecules that make up the system or the supra-molecular structure of these systems.
Biophysical chemists employ various tools used in physical chemistry to probe the structure of biological systems. These tools include spectroscopic methods like nuclear magnetic resonance (NMR) and X-ray diffraction. For example, the Nobel Prize in Chemistry in 2009 was based on x-ray diffraction studies of ribosomes.
Biophysical chemists study protein structure and the functional structure of cell membranes. For example, enzyme action can be explained in terms of the shape of a pocket in the protein molecule that matches the shape of the substrate molecule or its modification due to binding of a metal ion. Similarly, biophysical chemists study the structure and function of the biomembranes using model supramolecular structures. These include liposomes or phospholipid vesicles of different compositions and sizes.
The oldest well-known institute for biophysical chemistry is Max Planck Institute for Biophysical Chemistry in Göttingen. The Biophysics Department of King's College London is where the X-ray crystallography studies of DNA was done in the early 1950s.