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Enzymes (partial data) - Coggle Diagram
Enzymes (partial data)
Enzyme catalysis
Types of enzyme catalytic strategies
Metal ion catalysis
Metal ions function in a number of ways, including serving as an electrophilic catalyst or stabilizing intermediates
Metals form coordinate bonds (which are a little stronger than hydrogen bonds) with ligands
Metal ions can function as an electrophilic catalyst
About a third of all enzymes require a metal cofactor
Catalysis by approximation and orientation
The enzyme brings two substrates together in an orientation that facilitates catalysis
Binding with the enzyme reduces the rotational entropy of the substrates that would otherwise be randomly free floating in solutions, and this enables the correct positioning of substrates for the reaction
Acid-base catalysis
A molecule donates or accepts a proton
Bases can act as nucleophiles and vice versa
A base uses a lone pair of electrons to form a new bone with an acidic proton
Chymotrypsin also used acid/base catalysis
Histidine removes a proton from serine 195, generating a highly reactive alkoxide ion, which is a nucelophile
Covalent catalysis
The active site contains a nucleophile that is briefly covalently modified
A nucleophile is a chemistry that is attracted to regions of positive charge and electrophile is a chemical attracted to a negative charge
In the process of catalysis, serine 195 becomes a nucleophile that attacks the carbonyl group of protein substrate