l -Asparaginase from Proteus vulgaris

Abstract

To produce an immunologically and enzymologically new type of l -asparaginase, 108 strains of bacteria were screened for enzyme production. As a result, 13 bacteria belonging to the genera Alcaligenes, Bacterium , and Proteus were found to produce l -asparaginases in high levels. Among these l -asparaginases, partially purified l -asparaginases from B. cadaveris and P. vulgaris showed antitumor activity. A partially purified l -asparaginase preparation of P. vulgaris did not react with the antibody of Escherichia coli l -asparaginase on the Ouchterlony agar plate. Culture conditions for the production of l -asparaginase by P. vulgaris were investigated in detail. The enzyme was produced in high yields when cells were grown aerobically in a medium containing sodium fumarate and corn steep liquor. The addition of glucose or ammonium ion to the medium, however, resulted in depressed production of l -asparaginase. Under the optimum conditions, 3,700 international units of l -asparaginase was obtained from 1 liter of culture medium.