BIOCH 200 Enzymes (con’t) (March 7, 2014) some overlap
• *Chemical reactions only occur if the reactants are in the right orientation in
regards to each other
• Proximity and orientation effects of catalysis
o Substrate binding to enzyme is in a certain orientation
Bringing together substrates in this way greatly increases the rate
o *When enzymes catalyze reactions, they may donate/accept protons but
this is temporary… the enzyme will always return back to its original state.
• *Amino acids that take part in acid-base catalysis. Act as an acid or a base
depending on their state of protonation.
o Aspartate (or aspartic acid)
o Glutamate (or glutamic acid)
• *Amino acids that take part in nucleophillic catalysis (aka covalent catalysis).
These amino acids can act as nucleophiles when they get deprotonated because
they then have a lone pair of electrons, something that is needed for nucleophillic
• Schiff base = “imine”
• *Cofactors are divided into 2 groups o Coenzymes
Divided into two more groups:
• Cosubstrates (ex. NAD+)
o *Participate in the reaction within the active site and
then leave when it is over.