[Kinetics of the aspartate-aminotransferase reaction catalyzed by free and immobilized cells of E. coli].

The kinetics of the aspartate-aminotransferase reaction were studied, using free and immobilized cells of E. coli, strain 85 as an enzyme source. It was shown that the reaction is limited by mass transport of the reagents through the bacterial cell membrane even at high concentrations of the substrates in the surrounding solution. The polyacrylamide gel-incorporated cells of E. coli, strain 85 catalyze the aspartate-aminotransferase reaction more effectively as compared to free or destroyed cells. In the latter case the reaction is characterized by the following kinetic parameters: the effective values of the stationary rate of the product accumulation and its stationary efflux from the cell are equal to (15,37 +/- 0.4) . 10(-6) mole/s/mg of protein and (3,01 +/- 0,8) . 10(-20) mole/s per 1 cell. respectively. The steady-state constant for glutamate synthesis from aspartic acid is equal to 0,22--0,23.