L-asparaginase release from Escherichia coli cells with K2HPO4 and Triton X100

A method to release L-asparaginase (EC 3.5.1.1)from ATCC Escherichia coli 1 1303 cells by chemical permeabilization was studied. It was found that a co mbination of K2HPO4 and Triton X100 was effective. The influences of K2HPO4 concentration, Triton concentration, E. coli cell concentration and pH on the release of enzyme and proteins were investigated in detail. Experimenta l results showed that 12.5% (w/v) K2HPO4, 2% (w/v) Triton X100 and 3 x 10(8 ) cells/mL made the amount of enzyme released over 70%. L-Asparaginase in K 2HPO4 and Triton solution could remain stable at least for 24 h. The releas e effect of K2HPO4 and Triton X100 used simultaneously was better than that of K2HPO4 and Triton X100 used separately in succession. Electron microsco py indicated that the chemical treatment altered the surface structure off. coli cells but did not break them. As the method does not produce a large amount of cell fragments and the amount of enzyme released is relatively hi gh, it can be thought; to be an valuable and economic method to release int racellular enzyme.