Description. Ammonium sulfate precipitation is one of the most commonly used methods for protein purification from a solution. In solution, proteins form hydrogen bonds with water molecules through their exposed polar and ionic groups.When high concentrations of small, highly charged ions such as ammonium sulfate are added, these groups compete with the proteins to bind to the water molecules.This removes the water molecules from the protein and decreases its solubility, resulting in precipitation.n solution, proteins form hydrogen bonds with water molecules through their exposed polar and ionic groups. When high concentrations of small, highly charged ions such as ammonium sulfate are added, these groups compete with the proteins to bind to the water molecules.
In the UK, a PhD stands for âDoctor of Philosophyâ, sometimes referred to as a âdoctorateâ. It is the highest level of degree that a student can achieve. At some institutions, including Oxford University, a Doctor of Philosophy is known as a DPhil.
The Department's distance learning PhD is a three-year full-time or six-year part-time course in either subject area, depending on topic. Our students produce internationally-recognised research within one of our research clusters, with topics covering human history from prehistory to present.