Aerobic catabolism of threonine in Escherichia coli strain with feedback resistant biosynthetic threonine deaminase

摘要

The aerobic degradation of uniformly ~(14)C and ~(13)C labeled threonine was investigated in the threonine producing strain E. coli ITP290-3. This strain contains an integrated artificial operon P_(lac)-lacI-lvA~(7434), that allows to smoothly regulate the expression of threonine deaminase resistant to feedback inhibition. Products of fermentation of the ITP290-3 strain were analyzed with the help of TLC, GLC and heteronuclear [~1H, ~(13)C]-NMR spectroscopy. The analysis of experimental data has shown that propionate is a product of threonine instead of isoleucine degradation. Thus, it was established, that in E. coli cells an aerobic degradation of threonine into propionate occurs in the case when threonine is effectively deaminated by feedback resistant threonine deaminase.