[7] Adenylosuccinate lyase (ASL) is an enzyme that catalyzes two reactions in the de novo purine biosynthetic pathway.

In Thermotoga maritima, domain 1 contains 7 α-helices in residues 1-93, including the His68 which is highly conserved and was previously thought to be the catalytic acid in the active site.

[5] Adenylosuccinate lyase in humans and Bacillus subtilis can be competitively inhibited by the substrate analog adenosine phosphonobutyric acid 2’(3’), 5’-diphosphate (APBADP).

[5] More recent data conflicts with this idea and has confirmed that the mechanism is not in fact concerted, but that the abstraction occurs first and there is an intermediate carbanion species which is resonance stabilized.

[9] Experimental confirmation of the deprotonation, carbanion formation, and the rate-limiting step of protonation causing cleavage means this is an E1cb mechanism.

This condition is rare, and it presents with varying degrees of psychomotor retardation, autism, muscle wasting, and epilepsy.

[18] Normally these compounds are not present in the cerebrospinal fluid or urine because ASL acts on the majority of the substrate molecules before they can build up and be phosphorylated.

[19] It is thought that SAICA riboside may be the more toxic compound as it is found at higher levels in patients with severe clinical symptoms, and some researchers think S-Ado may even be protective.

[17] As resistance to anti-malarials increases, researchers are looking for new strategies to target the Plasmodium parasites which cause malaria, especially the more lethal P. falciparum.