This work aimed to develop a whole-cell biotransformation process for the production of α-ketoisocaproate from L-leucine. A recombinant Escherichia coli strain was constructed by expressing an L-amino acid deaminase from Proteus vulgaris. To enhance α-ketoisocaproate production, the reaction conditions were optimized as follows: whole-cell biocatalyst 0.8 g/L, leucine concentration 13.1 g/L, te...

The movement of the enormously enlarged filaments of Proleus vulgaris grown on penicillin agar ceased, or was slowed down, by screening the culture from the radiant heat of a microscope lamp. Organisms stimulated by heat after resting a short time in this way moved more rapidly than before. The increased activity was maintained for longer periods with longer rests, the increment in the period o...

As a result of chance observations, the authors studied for deoxyribonuclease activity 16 strains of Salmonella, including six fresh isolates and ten stock cultures, with positive results in 13. Reactions characteristically occurred at 48 hours or later, with the majority being manifest at 72 hours and the latest at six days. No other positive reaction was observed among approximately 7,000 Ent...

M.PvuII is a DNA methyltransferase from the bacterium Proteus vulgaris that catalyzes methylation of cytosine at the N4 position. This enzyme also displays promiscuous activity catalyzing methylation of adenine at the N6 position. In this work we use QM/MM methods to investigate the reaction mechanism of this promiscuous activity. We found that N6 methylation in M.PvuII takes place by means of ...