Argininosuccinate synthetase is an
enzyme that in humans is encoded by the ''ASS1''
gene.
The
protein encoded by this gene
catalyzes
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
the penultimate step of the
arginine biosynthetic pathway. There are approximately 10 to 14 copies of this gene including the
pseudogenes scattered across the
human genome, among which the one located on
chromosome 9 appears to be the only functional gene for argininosuccinate synthetase. Two
transcript variants encoding the same protein have been found for this gene.
Clinical significance
Mutations
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
in the
chromosome 9 copy of ASS cause
citrullinemia
Citrullinemia is an autosomal recessive urea cycle disorder that causes ammonia and other toxic substances to accumulate in the blood.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. .
Two for ...
.
40% to 90% of
bladder cancers are deficient in argininosuccinate synthetase.
Prognostic and therapeutic impact of argininosuccinate synthetase 1 control in bladder cancer as monitored longitudinally by PET imaging.
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References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Urea Cycle Disorders OverviewGeneReviews/NCBI/NIH/UW entry on Argininosuccinate Synthetase Deficiency; ASS Deficiency; Argininosuccinic Acid Synthetase Deficiency; CTLN1; Citrullinemia, Classic
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