FINALS BETTELHEIM 1 Flashcards
A biological catalyst.
With the exception of some RNAs that catalyze their own self-cleavage, all enzymes are proteins
Enzyme
catalyzes the hydrolysis of peptide bonds formed by the carboxyl group of lysine and arginine.
Trypsin
Oxidation-reduction reactions.
Oxidoreductases
Group transfer reactions.
Transferases
Hydrolysis reactions.
Hydrolases
Addition of two groups to a C–C double bond, or removal of two groups to create a C–C double bond.
Lyases
Isomerization reactions.
Isomerases
The joining to two molecules
Ligases (or synthetases)
The protein part of an enzyme
Apoenzyme
A nonprotein portion of an enzyme that is necessary for catalytic function; examples are metallic ions such as Zn2+ and Mg2+.
Cofactor
A nonprotein organic molecule, frequently a B
Coenzyme:
The compound or compounds whose reaction an enzyme catalyzes.
Substrate:
The specific portion of the enzyme to which a substrate binds during reaction
Active site:
A measure of how much a reaction rate is increased.
Enzyme activity
Any process that initiates or increases the activity of an enzyme.
Activation
: Any process that makes an active enzyme less active or inactive.
Inhibition
A substance that binds to the active site of an enzyme thereby preventing binding of substrate.
Competitive inhibitor
Any substance that binds to a portion of the enzyme other than the active site and thereby inhibits the activity of the enzyme.
Noncompetitive inhibitor
The active site becomes modified to accommodate the substrate.
Induced-fit model of an enzyme mechanism.
The inhibitor binds itself to a site other than the active site
allosterism
An enzyme-regulation process where the product of a series of enzyme-catalyzed reactions inhibits an earlier reaction in the sequence.
Feedback control
Binding of the regulator to a site other than the active site changes the shape of the active site.
The allosteric effect.
The process of affecting enzyme activity by covalently modifying it.
Protein modification
The best known examples of protein modification involve phosphorylation/dephosphorylation.
Protein modification
Isoenzyme (Isozymes
An enzyme that occurs in multiple forms; each catalyzes the same reaction.
