Question 2 - Inosine in AMP catabolism
Adenosine monophosphate (from now on referred to as AMP) is the lowest energy-containing nucleotide found in living organisms. In its degradation process (Figure 1), several enzymes and intermediates are required, playing important roles that regulate the correct functioning of the overall process. An alteration in any of those participants can cause severe consequences, such as immunosuppression. Inosine is one of those previously mentioned intermediates, formed in the first step of the AMP catabolism by the action of an enzyme known as adenosine deaminase (1).
Discussion o Why a blockade in its formation leads to severe immunosuppression?
Inosine, as it has been already mentioned,…show more content… NO is able to diffuse through the cell membrane easily, as it is lipid soluble while being only partially soluble in water, and it has a short half-life, no more than a few seconds, when it is in blood. Some of the actions it acts on are vasodilation, reduction of adhesion in endothelia and inhibition of platelet aggregation, among others (1).
Discussion o How it is synthesized?
Nitric oxide is liberated as a co-product in the conversion of L-arginine into L-citrulline in the presence of calmodulin and several co-factors such as NADPH, flavin mononucleotide (FMN), tetrahydrobiopterin (BH4) or flavin adenine dinucleotide (FAD), among others. This process (shown in Figure 2) is catalyzed by the nitric oxide synthases (NOS), a family of enzymes consisting of three different isoforms. The reaction takes place with an associated electron flux where the electron donor is NADPH, which gives two electrons to FAD, compound that then reduces FMN. This latter molecule transfers the electrons to the heme iron prosthetic group of NOS, turning it into Fe2+, which now binds to oxygen in order to oxygenate L-arginine (2),