rh Lecture 3 Slides
Feb 24, 2016
rh
Lecture 3 Slides
Michaelis-Menten Equation
Vo = Vmax S Km + S
again, a rectangular hyperbola MaudMenten
rh
Michaelis-Menten Equation
Vo = Vmax S Km + S
rh
when there is no S, V0 is also 0
as S gets big, V0 approaches Vmax
saturable
fig 6-11
box 6-1
Lineweaver-Burk: 1/S vs. 1/V
hyperbola becomes a line
1/Vo = Vmax S
Km + S
rh M & M inverted
Lineweaver-Burk Plot
box 6-1
Lineweaver-Burk: 1/S vs. 1/V
hyperbola becomes a line
In class I show a lotof fancy uses of theLB plot, but you just
need to know the basicdouble reciprocal plot!!!
box 6-1
Lineweaver-Burk: 1/S vs. 1/V
hyperbola becomes a line
BIOENERGETICSor
Free energy and life
part II intro-1
part II intro-3
part III intro-4
patterns inmetabolism
there aremany…
THE STORAGE and USE ofCHEMICAL ENERGY in
CELLULAR METABOLISM
DG = DH - TDS
Gibbsfree
energy
enthalpy(heat)
entropy(order)
“delta gee”- The change in free energy
entropy from increased numbers
?
- 1 atm pressure
- water at 55M
- pH = 7
- from initial concentrations of 1M
- temperature 25oC
K’eq is predicted by DG’o…
table 13-3
table 13-2
A 10-fold change in Keq
for each 1.4 kcal/mole
Actual free energy for a reaction
concentrationratio
when substrates are high- negative
when products are high- positive
Actual free energy for a reaction
concentrationratioHenri-Louis
Le Chatlier
adenosine triphosphate… ATP
adenosine triphosphate… ATP
The 20$ bill of the cell!!!
table 13-4
Hydrolysisof ATP
fig 13-11
fig 13-11
table 13-6
fig 13-9
[ATP][ADP][Pi]
Actual ATP hydrolysis energy
standard free energy= -30.5 kJ/mole
actual free energy= -51.8 kJ/mole
in erythrocyte
pg 494
free energies are additive!
spontaneitydetermined by whole setof reactions
fig 13-11
What is needed to lift this3 kg doginto the air?
Something heavier than 3 kg!!!
free energies are additive!
11kg
68kg
riddle: how do you lift 11 kg? ans: lower a weight > 11kg!
In metabolism,it is all about thecoupling mechanism
spontaneitydetermined by whole setof reactions
(fig 13-11 ed 4)
a mechanismof energy coupling
fig 13-8
Much of metabolism is aboutLEAVING GROUPS!!!
fig 13-8
C.R.H. Raetz
fig 13-10
adding a good leaving group to form a sigma bond…
palmitoyl-CoA + H2O palmitate + CoA-SH
This reaction is spontaneous in this direction… so how do we make run the reaction backwards?
Ans: couple it to the hydrolysis of ATP
making agood leavinggroup toform a sigma bond…
driving fancy chemistry by…making a good leaving group!
box 13-2