The
enzyme adenylosuccinate lyase (ADSL) intervenes twice in the biosynthesis of
adenine nucleotides.
ADSL deficiency is an inherited
metabolic disease characterized by various degrees of psychomotor retardation and accumulation of dephosphorylated
enzyme substrates 5-amino-4-imidazole-N-succinocarboxamide riboside (
SAICAr) and
succinyladenosine (SAdo) in body fluids. Severity of symptoms seems to correlate with residual activity of mutant
enzyme and with SAdo/
SAICAr concentration ratio in cerebrospinal fluid. To better understand the pathogenetic mechanisms of the disease symptoms, studies of catalytic properties of mutant
enzymes together with in vitro and in vivo experiments utilizing
SAICAr and SAdo must be performed. Such studies require availability of both ADSL substrates, 5-amino-4-imidazole-N-succinocarboxamide ribotide (
SAICAR) and
succinyladenosine 5'-monophosphate (
SAMP) and their dephosphorylated products in sufficient amounts and purity. Except for
SAMP, none of these compounds is commercially available and they must therefore be synthesized.
SAICAR was prepared by recombinant human ADSL-catalysed reaction of
AICAR (5-aminoimidazole-4-carboxamide) with
fumarate and isolated by thin-layer chromatography.
SAICAr and SAdo were prepared by calf intestine
alkaline phosphatase-catalysed dephosphorylation of
SAICAR and
SAMP and isolated on
cation- and
anion-exchange resin columns. The procedures described are easily scalable and provide high yields of sufficiently pure products for use in experiments related to studies of pathogenetic mechanisms in
ADSL deficiency.