InterPro domain: IPR009049

Argininosuccinate lyase (ASL or ASAL, 4.3.2.1 ) participates in arginine synthesis in all organisms catalysing the reversible breakdown of argininosuccinate to arginine and fumarate. The reaction is also part of the urea cycle [ 1 ]. The crystal structures of ASLs from several species have been studied, in particular the duck delta1 and delta2 eye lens crystallins, which are inactive and active homologues of ASL, respectively [ 2 ]. ASL is a member of the Lyase class I family, these proteins are active as tetramers. The four active sites of the homotetrameric enzyme are each formed by residues from three different subunits. In humans, mutations in ASAL result in the autosomal recessive disorder argininosuccinic aciduria [ 3 ].

This entry represents argininosuccinate lyase and includes avian delta crystallins whose biological role is to provide the optically clear cellular protein of the eye lens.

1. Structure determination and refinement at 2.44 A resolution of argininosuccinate lyase from Escherichia coli. Acta Crystallogr. D Biol. Crystallogr. 60, 1964-70
2. Mutational analysis of duck delta 2 crystallin and the structure of an inactive mutant with bound substrate provide insight into the enzymatic mechanism of argininosuccinate lyase. J. Biol. Chem. 277, 4166-75
3. Intragenic complementation and the structure and function of argininosuccinate lyase. Cell. Mol. Life Sci. 57, 1637-51