PROSITE documentation PDOC00488
Argininosuccinate synthase signatures


Argininosuccinate synthase (EC (AS) is a urea cycle enzyme that catalyzes the penultimate step in arginine biosynthesis: the ATP-dependent ligation of citrulline to aspartate to form argininosuccinate, AMP and pyrophosphate [1,2].

In humans, a defect in the AS gene causes citrullinemia, a genetic disease characterized by severe vomiting spells and mental retardation.

AS is a homotetrameric enzyme of chains of about 400 amino-acid residues. An arginine seems to be important for the enzyme's catalytic mechanism.

The sequences of AS from various prokaryotes, archaebacteria and eukaryotes show significant similarity. We selected two signature patterns for AS. The first is a highly conserved stretch of nine residues located in the N-terminal extremity of these enzymes, the second is derived from a conserved region which contains one of the conserved arginine residues.

Last update:

December 2004 / Patterns and text revised.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

ARGININOSUCCIN_SYN_1, PS00564; Argininosuccinate synthase signature 1  (PATTERN)

ARGININOSUCCIN_SYN_2, PS00565; Argininosuccinate synthase signature 2  (PATTERN)


1Authorsvan Vliet F. Crabeel M. Boyen A. Tricot C. Stalon V. Falmagne P. Nakamura Y. Baumberg S. Glansdorff N.
SourceGene 95:99-104(1990).

2AuthorsMorris C.J. Reeve J.N.
TitleConservation of structure in the human gene encoding argininosuccinate synthetase and the argG genes of the archaebacteria Methanosarcina barkeri MS and Methanococcus vannielii.
SourceJ. Bacteriol. 170:3125-3130(1988).
PubMed ID3133361

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