the Michaelis-Menten equation

chem further

derivation

is so small when that it is ignored

the steady state assumption is made:

• the rate of formation of enzyme-substrate complex is the same as the rate of enzyme-substrate dissociation

michaelis constant:

initial reaction velocity is dependent upon the rate at which the enzyme-substrate complex dissociates into enzyme and product

• rate determining step

another assumption is made here, that there is a point called , which is the point at which all the enzyme-substrate complex possible is formed (note that the enzyme is limiting reagent ) and there is no enzyme left to form form the enzyme-substrate complex

• there exists a point, , where all the enzyme is completely saturated with substrate, no free enzyme,
• so

and here we have arrived at the michaelis-menten equation

what does mean?

when ,

represents the reciprocal of enzyme-substrate affinity

• low means high substrate affinity as it readily forms the enzyme-substrate complex even at low substrate concentrations
• high means low substrate affinity

can tell us how much substrate the enzyme can take on
with low km, it can’t take on a lot because it has high affinity
with high km and low substrate affinity, it can take on larger amounts of substrate

see forms of enzyme inhibition

lineweaver-burk plot