Enzyme Mechanisms Flashcards
What are the four types of enzymatic regulation?
1) Non-covalent modification (inhibitor, activator) 2) Covalent modification (inhibitor, activator) 3) Irreversible (at the protein level) 4) Reversible ( at the protein level)
Allostery
Non-covalent modification; binding of a ligand at one site of an enzyme causes differences in binding at different site; allosteric proteins usually have multiple subunits; allostery appears to modify Km.
What four amino acid commonly phosphorylated?
Ser, Thr, Tyr, His
What amino acid is commonly adenylated?
Tyr
What enzyme catalyzes the addition of a phosphate group?
Phosphorylase
What enzyme catalyzes the addition of AMP or an adenyl group?
Adenylase
Ubiquitination
The process by which the protein ubiquin is added to a compound; associated with Lys; Poly marks target for degradation; Mono- changes activity
What types of modifications are used to modify enzyme activity?
1) Phosphorylation, Adenylation, ubiquitination, addition of a hydrophobic group, cellular pH.
SCCAM
Five Mechanisms of catalysis (Strain, Covalent, Cage-effect, Acid-base, Metal ion)
What are the 6 enzyme classes?
HOT LILY; 312456; Hydrolase, Oxidoreductase, Transferase, Lyase, isomerase, ligase.
Oxidoreductase
EC: 1; Mechanism of catalysis Transfer of electrons
What are the three types of oxidoreductases?
1st, Oxidoreductases transfer electrons; Dehydrogenase, Oxidase, Oxygenase
Dehydrogenase
Oxidoreductase; Transfer of a hydrogen from donor to acceptor
Oxidase
Oxidoreductase; Transfer of hydrogen (or e-) from donor to oxygen
Oxygenase
oxidoreductase; Incorporation of oxygen into a substrate
Transferase
EC 2; enzyme mechanism; transfer functional groups (two types Kinase and Transaminase)
Kinase
Transferase; Transfer of a phosphoryl group
Transaminase
Transferase; Transfer of an amino group to a keto group
Hydrolase
EC 3; Single bond cleavage by water incorporation; two types (phosphatase, sulfatase)
Phosphatase
Hydrolase; Removal of phosphate groups
Sulfatase
Hydrolase; Removal of sulfate groups
Lyase
EC 4; Bond cleavage by elimination; naming (hydro-lase; thio-lyase.. etc.)
Isomerase
EC 5; Intramolecular group transfer; two types (mutase, epimerase)
Mutase
Isomerase; intramolecular group transfer
Epimerase
Isomerase; conversion of chirality at one carbon atom
Ligase
EC 6; Joining two molecules; ATP dependent
Synthetase
Ligase; A common name for ligase.
Nucleophile
a compound with a strong tendance to donate electrons
Electrophile
a compound with a strong tendency to accept electrons
Hexokinase
look at the suffix!! It is a kinase. A kinase is a transferase, this works in glycolysis; uses the cage effect and induced fit
