Enzymes Flashcards
Enzymes act upon ________ to produce _______ .
Substrates; Products
Enzymes transiently disrupt _______ .
Homeostasis
What is the complementary class of enzymes of Cyclases?
Phosphodiesterases
What is the complementary class of enzymes to synthases?
Proteases, Lipases
What is the complementary class of enzymes of Kinases?
Phophostases
What is the function of Cyclases?
production of cyclic nucleotides
Calmodulin
An endogenous calcium binding protein that can bind 4 Ca2+ ions; can also be a signaling molecule; activates AC
Forskolin
A plant derived phorbol ester toxin; activates AC
PKA
cAMP dependent protein kinase; binding 2 molecules of cAMP to each of the 2 regulatory subunits of PKA releases the 2 catalytic subunits
How many classes of phosphodiesterases are there?
7
What does a phosphodiesterase convert cAMP/cGMP to?
5’ cAMP/cGMP
What are some inhibitors of phosphodiesterases?
Caffeine, theophylline, IBMX, sildenifil (viagra), vardenafil (levitra), tadalafil (cialis)
NOS produces NO and is an example of a ______.
Synthase (nitric oxide synthase)
NO is a ________ neurotransmitter.
Retrograde; it goes from the post synaptic cell to the pre synaptic cell
PLC is an example of a _________.
Phosphotase
What does PLC do?
Cleaves PIP2 into DAG and IP3
PKC is an example of a _________.
Kinase
What activates PKC?
DAG, free Ca2+, and ATP
What are the isoforms of PKC?
α, β, γ, ε, ζ
The ____________ of different isoforms of PKC are highly conserved.
Catalytic domains
Active PKC is membrane bound because
DAG is required for its activation, and DAG is membrane bound
IP3 activates
An intracellular IP3 receptor
There are __________ of Ca2+ ions in the ER.
Hundreds of millions
Calcium ATP-ase (the calcium pump) pumps Ca2+ _________ the ER.
Into
The IP3 receptor _________ Ca2+ sequestered within the ER
Releases
The ER ATP-ase is activated by ______.
CaM
Enzymes are catalysts; they lower the ______ of a reaction.
Activation Energy
