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Characterization and Partial Purification of L-Asparaginase from Corynebacterium Glutamicum

1990; Microbiology Society; Volume: 136; Issue: 3 Linguagem: Inglês

10.1099/00221287-136-3-515

2059-9323

Juan M. Mesas, José A. Gil, Juan F. Martı́n,

Acute Lymphoblastic Leukemia research

A high l-asparaginase (l-asparagine amidohydrolase; EC 3.5.1.1) activity was found under conditions of lysine overproduction in cultures of Corynebacterium glutamicum. l-Asparaginase was purified 98-fold by protamine sulphate precipitation, DEAE-Sephacel anion exchange, ammonium sulphate precipitation and Sephacryl S-200 gel filtration. The asparaginase protein was subjected to PAGE under non-denaturing conditions, identified by an in situ reaction and eluted from the gel in an active form. The estimated M r from gel filtration and SDS-PAGE was 80000. The l-asparaginase activity was inhibited by the l-asparagine analogue 5-diazo-4-oxo-l-norvaline. Neither d-asparagine nor l-glutamine was a substrate for the enzyme. l-Asparaginase was produced constitutively; its role may be that of an overflow enzyme, converting excess asparagine into aspartic acid, the direct precursor of lysine and threonine.