Glutamine amidotransferase, class-II <p>A large group of biosynthetic enzymes are able to catalyse the removal of the ammonia group from glutamine andthen to transfer this group to a substrate to form a new carbon-nitrogen group. This catalytic activity is known asglutamine amidotransferase (GATase) (<db_xref db="EC" dbkey="2.4.2"/>) [<cite idref="PUB00000003"/>]. The GATase domain exists either as a separate polypeptidicsubunit or as part of a larger polypeptide fused in different ways to a synthase domain. On the basis of sequencesimilarities two classes of GATase domains have been identified [<cite idref="PUB00002062"/>, <cite idref="PUB00002406"/>], class-I (also known astrpG-type) and class-II (also known as purF-type). Enzymes containing Class-II GATase domains include amidophosphoribosyltransferase (glutamine phosphoribosylpyrophosphate amidotransferase) (<db_xref db="EC" dbkey="2.4.2.14"/>), which catalyses thefirst step in purine biosynthesis (gene purF in bacteria, ADE4 in yeast); glucosamine--fructose-6-phosphate aminotransferase(<db_xref db="EC" dbkey="2.6.1.16"/>), which catalyses the formation of glucosamine 6-phosphate from fructose 6-phosphate and glutamine(gene glmS in <taxon tax_id="562">Escherichia coli</taxon>, nodM in Rhizobium, GFA1 in yeast); and asparagine synthetase (glutamine-hydrolizing) (<db_xref db="EC" dbkey="6.3.5.4"/>), which is responsible for the synthesis of asparagine from aspartate and glutamine. A cysteine is present at the N-terminal extremity of the mature form of all these enzymes.</p><p>This domain is found in a number of cysteine peptidases belonging to MEROPS peptidase family C44 and their non-peptidase homologs. </p>