BIO315H5 Chapter 3: BIO315 Chapter 3 - p.157-160
Document Summary
Gtp binding proteins determine whether gtp or gdp is bound. Ras is inactivated by gap gap binds to ras and induces ras to hydrolyze gtp to gdp (during this process, phosphate is released) Ras protein stays inactive, gdp bound until it encounters gef gef binds to gdp bound ras and causes ras to release gdp. When gdp is released, its replaced with gtp; gef then adds phosphate back which activates ras. Ubiquitin can be covalently attached to target protein in many ways: Polyubiquitin the first ubiquitin is attached to target and each subsequent ubiquitin links to lys of the previous ubiqutitin creating a chain of lysine linked ubiquitin. It"s attached to a single lysine side chain on target. It directs protein to proteasome where it"s digested. Carboxyl end of ubiquitin needs to be activated. Activation is done by e1 which uses atp hydrolysis to attach ubiquitin. E1 then gives activated ubiquitin to e2 (conjugator)
