Asparagine synthetase is an enzyme that generates asparagine from aspartate. This amidation reaction is similar to that promoted by glutamine synthetase.human ASNS based on its ability to complement ts11, a temperature-sensitive (ts) mutant of the BHK hamster cell line that at the nonpermissive temperature is blocked in progression through the G1 phase of the cell growth cycle. The gene was transcribed into an mRNA of 2 kb that was expressed in all human, hamster, and mouse cell lines tested. It encodes a protein of about 550aa. The 5-prime upstream region of this gene, like other housekeeping genes, lacks conventional TATA and CAAT boxes. Both the human and the hamster genes have a high 5-prime G+C content which may play a role in expression through DNA methylation.