L-asparaginase (... as-PAYR-uh-jih-NAYS)
A drug that is used to treat acute lymphoblastic leukemia (ALL) and is being studied in the treatment of some other types of cancer. It is an enzyme taken from the bacterium Escherichia coli (E. coli). It breaks down the amino acid asparagine and may block the growth of tumor cells that need asparagine to grow. Also called asparaginase and Elspar.