Asparagine Synthetase/ASNS Proteins and Enzymes

Asparagine synthetase (AS) is a housekeeping enzyme responsible for the production of asparagine from aspartate and glutamine. Most mammalian cells express AS and regulate the level of activity in response to the concentration of asparagine in the medium. Certain tumor cells in contrast, exhibit little or no AS activity and rely on the surrounding medium as a source of exogenous asparagines (1). Therefore tumor cells may be selectively killed by a chemotherapeutic drug using asparaginase. This approach has been exploited in the treatment of certain cancers like childhood acute lymphoblastic leukemia (2).