Lecture 13 - Enzymes III Flashcards
ATCase acts as a(n) ______ of pyrimidine synthesis depending on CTP vs ATP binding.
ATCase regulatory and catalytic subunits are bound to each other by ____
a zinc domain
CTP works to “lock” ATCase into the ____-state (doesn’t bind substrate)
tense or “T-state”
When in the T-state, ATCase does or does not produce pyrimidines
This class of enzyme adds inorganic phosphates to proteins
This class of enzyme removes inorganic phosphates from proteins
Why is AMP a potent regulator of enzymes (specifically kinases)?
AMP is produced when Pi is removed from ATP (as a result of cellular E* stores being low). AMP activates kinases to produce more ATP by phosphorylation
What is the name of an inactive protein that is awaiting cleavage to become active?
Pepsinogen is one of the few protease zymogens found in the _____
Two types of allosteric control in enzymes
Inhibition and activation
All substrates must bind to the enzyme prior to product release in this type of bisubstrate reactions
What is “sequential reactions?”
One substrate binds, product is released, then another substrate binds to enzyme in this type of bisubstrate reaction.
What is the (+) allosteric regulator for ATCase? Why is this particular molecule an ATCase inhibitor?
ATP; ATP is the byproduct of purine synthesis-therefore, increased ATP signifies that the “competing” purine pathway is more active. Since purines bind pyrimidines, it makes sense to increase pyrimidine synthesis!!!
Acts to dephosphorylate adenyl cyclase when intracellular calcium is high
PP2B (aka “calcineurin”)