l-
Asparaginase is now known to be a potent
antineoplastic agent in animals and has given complete remission in some human
leukemias. Extensive clinical trials of this
enzyme, however, were not possible in the past because of inadequate production of this substance. We have developed practical procedures for producing l-
asparaginase in yields of sufficient quantity and purity for more extensive clinical evaluation. The nutritional requirements for optimal production of biologically active l-
asparaginase by a strain of Escherichia coli have been ascertained. The highest yields of
enzyme were obtained when cells were grown aerobically in a corn steep medium. Good
enzyme production was associated with media containing
l-glutamic acid,
l-methionine, and
lactic acid. The addition of
glucose to the medium, however, resulted in depressed production of l-
asparaginase.
Sodium ion appeared to suppress l-
asparaginase production. With the procedure described for isolation of biologically active l-
asparaginase from E. coli, stable l-
asparaginase preparations with a specific activity of 620 IU per mg of
protein (1,240-fold purification with 40% total recovery) were obtained.