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BIBC 102 ANNOUNCEMENTS. Randy ’ s bipartite office hours Tue 2 :30 -3:30 pm Wed 2:30-3:30 pm 2130 Pacific Hall. BIBC 102 Web Site. http://courses.ucsd.edu/rhampton/bibc102/. Soft Reserves lecture slides are available. Near Hi Thai. . BIBC 102 ANNOUNCEMENTS. BIBC 102 ANNOUNCEMENTS.
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BIBC 102 ANNOUNCEMENTS Randy’s bipartite office hours Tue 2:30-3:30 pm Wed 2:30-3:30 pm 2130 Pacific Hall BIBC 102 Web Site http://courses.ucsd.edu/rhampton/bibc102/ Soft Reserves lecture slides are available. Near Hi Thai.
BIBC 102 ANNOUNCEMENTS Principles of Biochemistry,6th ed Lehninger, Nelson and Cox Will be on reserve at the Biomedical Library, but not Geisel Library
What is the relation between changes in activation energy and reaction rate?
Activation energy and reaction rate k dS/dt = k[S] S P blue terms are constant when temperature is constant...
Activation energy and reaction rate designate blue terms as constants
Activation energy and reaction rate call DG‡ = A for simplicity
Lowering activation energy … the rate constant is increased by this factor: note the following features: lowering DG‡ makes reaction faster identical effect on both directions when DG‡ is lowered by this amount:d
how big a deal is this? recall thatC2= RT at body temp, RT= 2573 J/mole so if DG‡changes by the value of one hydrogen bond (~20 kJ/mole) rate enhancement is e7.8 = 2440
If you have not already please read LIGAND BINDING and ENZYME CATALYSIS
If you have not already please read LIGAND BINDING and ENZYME CATALYSIS
Does this form make intuitive sense? when there is no L, LB is also 0 as L gets big, LB approaches B saturable rh
Binding isotherm rectangular hyperbola rh
Enzyme kinetics: binding and beyond when there is no S, reaction rate is 0 as S gets big, rate reaches a maximum saturable rh
Maud Menten VmaxS Vo = Km + S Michaelis-Menten Equation again, a rectangular hyperbola rh
VmaxS Vo = Km + S Michaelis-Menten Equation when there is no S, V0 is also 0 as S gets big, V0 approaches Vmax saturable rh
how fast can an enzyme “do” a reaction? Vmax = kcat[E]T table 6-7
Competition for binding remember to tell them about I and Y feature of saturability rh
action of a uncompetitive inhibitor fig 6-15
a “suicide” inhibitor catalytic action of enzyme causes permanent covalent inhibition fig 6-16
CHYMOTRYPSIN: a protease fig 6-18
catalytic triad fig 6-21
amprenavir Agenerase® Why do we need these details? an example: The HIV Protease: cleaves single HIV-encoded polypeptide into various proteins needed for viral replication Specific inhibitors of the HIV protease were developed by an intimate understanding of the structure and mechanism of the enzyme
Now many HIV protease inhibitors fig 6-30
hexokinase reaction pg 212
hexokinase fig 6-22
hexokinase induced fit fig 6-22
site of Pi transfer fig 6-22
C6 ATP ATP glucose transfer of P from ATP xyulose hydrolysis of ATP
Regulation by phosphorylation: general case switchable changes in activity can activate or diminish activity
phosphorylation of glycogen phosphorylase dephosphorylated enzyme less active phosphorylated enzyme more active fig 6-36 ish