Sir Tim Hunt, FRS
(born Richard Timothy Hunt; 19 February 1943 in Neston, Cheshire)
is an English biochemist.
Tim Hunt was awarded the 2001 Nobel Prize in Physiology or Medicine with Paul Nurse and Leland H. Hartwell for their discoveries of protein molecules that control the division (duplication) of cells.
When cells with nuclei divide, they divide in phases called G1 (growth), S (synthesis), G2 (growth), and M (mitosis). Nurse, Hartwell and Hunt together discovered two proteins, cyclin and CDK (cyclin dependent kinase), that control the transition from one stage to another. These proteins are called checkpoints, because they check whether the cell has divided properly. If the cell doesn't divide correctly, other proteins will attempt to repair it, and if unsuccessful, they will destroy the cell. If a cell divides incorrectly and survives, it can cause cancer and other serious diseases.
Working in sea urchin eggs, Hunt discovered cyclins, proteins that bind to cyclin dependent kinase (CDK) proteins and regulate their activity. Cyclins and CDKs turn other cell cycle proteins on and off by adding or removing phosphate groups.