Biochemical studies of the enzyme have focused on proteins of ADSL from nonhuman species, the ADSL structure from the crystallized protein of Thermotoga maritime has been used, along with DNA sequencing data, to construct homology models for a variety of other organisms, including human ADSL. A variety of studies have been done using the equivalent enzyme from Bacillus subtilis, which shares a significant percentage of identity along with about some percentage of similarity in amino acid sequence with the human enzyme. Homology models overlaid on each other show a high degree of overlap between the enzymes.The family of enzymes to which ADSL belongs and that catalyze β-eliminations in which fumarate is one of the products are homotetramers with four active sites composed of amino acid residues from three distinct subunits. Much is known about the active site of human ADSL due to studies of the active site in the B. subtilis ADSL through affinity labeling and site-directed mutagenesis. While there is some variability among species in the sequencing of ADSL, the active site of the enzyme contains many residues that are conserved across species and have been shown to be critical to the enzymes function. His68 and His141 seem to serve as the general acid and base catalysts, and are critical to the catalyzing reaction of the substrate. His89 seems to enhance the binding of the substrates phosphoryl group and orient adenylosuccinate for catalysis. All three histidines are conserved throughout the 28 species for which the structure of ADSL is known.
Glu275 and Lys268 have also been shown to contribute to the active site, indicating there are four active sites, each of which is formed from regions of three subunits. ADSL deficiency in different people is often caused by different mutations to the enzyme, more than 50 different mutations in the ADSL gene have been discovered

Diagnosis
In terms of the diagnosis of adenylosuccinate lyase deficiency one should look for (or exam/method):
MRI
Demonstration of succinylpurines in extracellular fluids like plasma, cerebrospinal fluid and/or urine using high-pressure liquid chromatography, with or without mass spectroscopy
Genetic testing - genomic cDNA sequencing of the ADSL gene and characterization of mutant proteins. Treatment
Treatment of adenylosuccinate lyase deficiency can be done via epilepsy management with anticonvulsive drugs. Additionally the following options include:

D-ribose and uridine administration
Ketogenic diet
S-adenosyl-l-methionine

Prognosis
The prognosis of this condition in childhood usually has a stable outcome, whereas in neonatal is almost always fatal, according to Jurecka, et al. See also
Adenylosuccinate
Adenylosuccinate lyase
List of genetic disorders

References
Further reading
Saudubray, Jean-Marie; Berghe, Georges van den; Walter, John H. (2011-11-16). Inborn Metabolic Diseases: Diagnosis and Treatment. Springer Science & Business Media. ISBN 9783642157202. Blau, Nenad; Hoffmann, Georg F.; Leonard, J. V.; Clarke, Joe T. R. (2006-01-16). Physicians Guide to the Treatment and Follow-Up of Metabolic Diseases. Springer Science & Business Media. ISBN 9783540289623. == External links ==