Induced fit model of Enzyme-Substrate interaction
Posted by biochemistryquestions on July 15, 2008
Answer to Question E-05
b) Induced fit
The Induced fit model describes the formation of the E-S as a result of the interaction between the substrate and a flexible active site. The substrate produces changes in the conformation on the enzyme, aligning properly the groups in the enzyme. It allows better binding and catalytic effects.
This model opposes to the former Lock and Key model (c) , that explained the formation of the E-S complex as a result of the binding of complementary geometrical rigid structures, as a lock and a key.
Follow this link to find a very good animation that represents these two models:
http://www.wiley.com/legacy/college/boyer/0470003790/animations/enzyme_binding/enzyme_binding.htm
The Concerted model (a) and the Sequential model (e) are models used to explain the allosteric changes of conformation of an enzyme from the T structure to the R structure and viceversa. In the concerted model all the subunits that form the allosteric protein change conformation at once, while in the sequential model the change in conformation of one subunit favors the change in conformation of the other subunits and so on.
The Michaellis Menten model (d) is related to the kinetics of enzyme catalyzed reactions, and describes the relationship between the concentration of substrate and enzyme velocity in a reaction where no allosteric effects exist.
More information about:
Michaelis Menten model:
http://themedicalbiochemistrypage.org/enzyme-kinetics.html#michaelis
http://en.wikipedia.org/wiki/Michaelis-Menten_kinetics
Induced fit model:
http://themedicalbiochemistrypage.org/enzyme-kinetics.html#interactions
Concerted Model and Sequential Model:
http://www.aw-bc.com/mathews/ch07/c07hsob.htm
http://en.wikipedia.org/wiki/Allosteric_regulation
http://www-ssrl.slac.stanford.edu/research/highlights_archive/allosteric_transition.html
