Michaelis-Menten Equation

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