Module 4: Proteins -Enzymes/Immune System Flashcards
Enzymes
catalyze biochemical reactions
make biochemical reactions go faster (reduces Ea)
do not get used up in the reaction
Gibbs Free Energy of Activation (Gǂ)
equal to the difference in Free energy between the Transition state and substrate (S)
Gibbs free energy change (G)
difference between substrate (S) and product (P)
deltaG free energy is negative…
reaction is favourable
proceeds in the forward direction
deltaG free energy is positive…
reaction is unfavourable
proceeds in the backward direction
enthalpy (H)
heat energy in the system
to decrease activation energy, activation enthalpy is more negative while the activation entropy is more positive
entropy (S)
measure of disorder
to decrease activation energy, activation enthalpy is more negative while the activation entropy is more positive
Catalytic site/active site
allows for tight binding of substrate in fixed orientation
How can enthalpy (H) become more negative?
accomplished by weakening C=O bond
can be done by adding positive charge R close to carbonyl ensuring active site scaffold better accommodates tetrahedral TS intermediate
How can entropy (S) become more positive?
binding substrate
free to fixed orientation
Lock and Key model
emphasized enzyme-substrate (ES) complementarity, however it did not delve into the details of how the ES complex goes on to form the product, P
binding not flexible/adaptive
Induced Fit model
conformational flexibility of the enzyme’s binding pocket
1) Conformation change in the enzyme results in moving the substrate towards its highly reactive transition state
2) Formation of the product very quickly leads to dissociation of the product from the enzyme active site and subsequent recycling of the enzyme for another reaction
Immune System
protect us from pathogens like bacteria, viruses and other foreign material that we encounter
Anatomical barriers
innate response
encounters pathogens before they get into our bloodstream and our cells
ex: skin, mucous membrane, stomach acid
Humoral barriers
innate response
mediated by substances found in our humours or body fluids
ex: inflammatory response
