Catalytic mechanisms Flashcards
Covalent catalysis is what
Formation of covalent intermediates, change reaction paths
General Acid-Base catalysis is what
enzymes act as intermediate proton donors/acceptors
Metal Ion catalysis is what
Electrophic, shift pKa
Catalysis by approximation is what?
Enzyme brings substrates close together
Enzymes also control water at what
At the water active site
Nucleophiles have what charge?
Negative charge
Electrophiles have what charge?
Positive charge
look at general base and acid catalysis again
ok
Covalent catalysis requires what
A nucleophile on the enzyme
The general acid form of the amino acid is what
Proton donor, protonated
The general base form of the amino acid is what
Proton acceptor,deprotonated
What amino acids can act asa nucleophile
Reactive serine, cysteine, histidine, tyrosine, lysine/arg, amine, or carboxylate (eg aspartate)
pH can affect what?
(1) the binding of the substrate (2) the ionization state of the amino acids involved in catalysis (3) the ionization state of the substrate (4) The variation in protein structure (at extremes of pH)
