| Asparaginase, which is found in various plant, animal and bacterial cells, catalyses the deamination of asparagine to yield aspartic acid and an ammonium ion, resulting in a depletion of free circulatory asparagine in plasma PUBMED:3026924. The enzyme is effective in the treatment of human malignant lymphomas, which have a diminished capacity to produce asparagine synthetase: in order to survive, such cells absorb asparagine from blood plasma PUBMED:2407723, PUBMED:3379033 - if Asn levels have been depleted by injection of asparaginase, the lymphoma cells die.