Brar - Enzyme Regulation Flashcards
How do competitive inhibitors work?
compete with substrate for the active site, closely resemble substrate, and they RAISE the apparent Km
How an competitive inhibitors be overcome?
Can be overcome by increasing substrate concentration
How do competitive inhibitors affect Vmax?
NO effect on Vmax
Vmax stays the same!!!
When are noncompetitive inhibitors usually seen/used?
In multi-substrate reactions
What does a noncompetitive inhibitor do?
lowers the concentration of effective enzyme and lowers Vmax
How is Km affected by a noncompetitive inhibitor?
It has NO effect on the Km!!!
List 6 ways enzyme reaction velocity can be regulated
inhibitors, allosteric molecules, production of inactive precursors, protein-protein interactions, and feedback inhibition
Give two examples of protein-protein interaction?
G proteins and calcium dependent calmodulin
What are allosteric molecules?
activators and inhibitors that induce a conformational change in an enzyme and change its affinity
Where do allosteric molecules bind?
bind at the allosteric site which is completely separate from the active site
What do allosteric inhibitors have a more profound effect on?
enzyme velocity; more so than competitive and noncompetitive inhibitors
Do allosteric effectors mimic or resemble substrates?
NO, not at all.
What is covalent modification?
conformational changes induced by direct chemical modification
What is an important covalent modification?
PHOSPHORYLATION
What is feedback inhibition?
when the end product of a rxn allosterically inhibits its own synthesis. inhibits a committed step
