L-Asparaginases (EC 3.5.1.1) hydrolyze L-asparagine to L-aspartate and ammonia. Enzymes with asparaginase activity play an important role in the metabolism of all living organisms [1,2]. Enzymes capable of converting L-asparagine to L-aspartate can be classified as bacterial-type or plant-type L-asparaginase. Bacterial-type L-asparaginase are further divided into subtypes I and II, defined by their intra-/extra-cellular localization, substrate affinity, and oligomeric form. Homologous bacterial-type L-asparaginase are found in all kingdoms of life. Furthermore, bacterial-type L-asparaginase are related to other enzymes, including:

• Bacterial L-glutaminase-asparaginase (EC 3.5.1.38).
• Archaeal GatD subunit of Glu-tRNA amidotransferase (Glu-AdT).
• Mammalian lysophospholipase (EC 3.1.1.5), which is believed to play a major role in the hydrolytic degradation of lysophosphatidylcholine.

The asparaginase/glutaminase domain consists of two α/β subdomains that are connected by an extended but structured linker region. The larger N-terminal subdomain is characterized by an eight-stranded antiparallel mixed β-sheet. The smaller C-terminal subdomain contains a parallel β-sheet (see <PDB:2JK0>) [3].

Two conserved threonine residues have been shown [4,5] to play a catalytic role. One of them is located in the N-terminal extremity while the second is located at the end of the first third of the sequence. We used both conserved regions as signature patterns.

The profile we developed covers the entire asparaginase/glutaminase domain.