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.
Traditionally, a PhD involves three to four years of full-time study (can be six years or more if studied part-time), in which the student completes a substantial piece of original research presented as a thesis or dissertation.ost institutions require that candidates hold an honors degree or a masterâs degree with high academic standing, along with a bachelorâs degree with at least upper second-class honors. In some cases, you can also apply for a PhD simply on the basis of your masterâs degree grades.