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10 Cards in this Set
- Front
- Back
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name two types of enzyme regulation via covalent modification.
which type is reversible? |
Proteolysis - cleaves PEPTIDE bonds specifically
phosphorylation - is reversible! |
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where does the end-product in feedback inhibition act in the rxn sequence?
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always at the rate limiting step or step unique to pathway.
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are allosteric inhibitors reversible?
what kind of enzyme kinetics to allosteric inhibitors follow? |
yes.
SIGMOIDAL. |
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allosteric enzymes tend to stabilize what state?
pushes curve which way? |
T state -
pushes curve to the -----> right. |
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what does K0.5 mean?
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1/2 of the enzyme is in T state and half is in R state.
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Describe the steps in the ATC-ase rxn for allosteric regulation.
What allosterically inhibits this rxn? What allosterically activates this? |
asp + carbamoyl phosphate (ATC-ASE)--->N-carbamoylasp (ATP)-->(ATP)--->CTP
CTP INHIBITS THIS ATP ACTIVATES THIS |
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What does CTP actually do to inhibit the ATC-ase rxn?
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binds to regulatory subunit on ATC-ase and locks it in T state -pushing the curve to the RIGHT ---->
K0.5 is INCREASED |
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What state does ATP push ATC-ase rxn toward?
What happens to K0.5? |
ATP ACTIVATES this rxn...pushing the curve <---- LEFT toward the R state.
K0.5 is decreased |
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Is the LDH isozyme H4 or M4 inhibited by allosterically inhibited by pyruvate?
Why? |
H4 is allosterically inhibited by buildup of pyruvate.
It allows aerobic respiration to occur as long as possible. |
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Carboxylation, hydroxylation, N-glycosylation, O-glycosylation and phosphorylation are examples of what kind of enzyme regulation?
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Short acting covalent R-group modifications.
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