Enzyme Regulation Flashcards
Homoallosteric
Cooperative binding
Heteroallosteric
Cooperative binding and positive/negative regulators
Allosteric activators bind tightly to
R state
Allosteric inhibitors bind tightly to
T state
S0.5 is the same as
Km
binding of allosteric activator makes graph more
Hyperbolic, shifts to the left
When is gluconeogenesis activated
High ATP
Low ADP/AMP
When is glycolysis activated
Low ATP
High ADP/AMP
Exercise
Low ATP
High ADP/AMP
Rest
High ATP
Low ADP/AMP
Reversible covalent modification
Coordinated response of several enzymes to a single signal
What catalyzes first step in glycogenolysis
Glycogen phosphorylase
Glycogen phosphorylase is both
Allosteric effector
Reversible covalent modification
Phosphorylase is activated by
high AMP/ADP (allosterically activates to R form)
OR adrenaline
PKA is activated by
cAMP, a second messenger
Phosphorylation is reversed by
Protein phosphatase
Glycogen phosphorylase is activated by
Caldmodulin which is activated by AMP
Calmodulin is activated when binded to
Ca2+
Increase in Ca2+ stimulates
glycogenolysis (breaking down glycogen)
G proteins
Hydrolyzes GTP –> Releases target
Reaction is slow
Proteolytic cleavage is
irreversible
What are inactive protein forms
Proprotein, proenzyme, zymogen
What activates zymogen
Proteolytic cleavage
What enzyme is synthesized in zymogen form
Chymotrypsin, synthesized in pancrease in inactive form
