10 Questions
What is the role of BH4 in NOS?
Coupling the reductase and oxygenase domains
What binds the substrate L-arginine and cofactor tetrahydrobiopterin (BH4) in NOS?
Tetrahedral coordination of a zinc ion
What is the product of the reaction between the Fe2+-O2 complex and the guanidine moiety of L-arginine?
L-citrulline and NO
What is the purpose of the linker region in NOS?
Binding calmodulin
What is the role of the zinc ion in the normal coupled state of NOS?
Stabilize the NOS dimer
What is the net effect of the Fe3+ center of the heme being reduced to the ferrous (Fe2+) center?
The Fe2+-O2 complex reacts with molecular oxygen
What is the consequence of BH4 scarcity on NOS?
NOS remains as a monomer and fails to bind L-arginine
What is the byproduct of the uncoupled NOS reaction?
Superoxide (O2−)
What is a major cause of NO deficiency in chronic disorders?
Deficiency of BH4
What is the result of BH4 deficiency on the body?
Tissue fibrosis and stiffening
Learn about the structure and function of Nitric Oxide Synthase (NOS), including its dimeric composition, substrate binding, and enzymatic activity. Understand the role of the zinc ion, L-arginine, and tetrahydrobiopterin (BH4) in NOS function. Discover the organization of the NOS monomer into distinct domains and their connections.
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