Browsing Pathways

Methylglyoxal, also known as pyruvaldehyde, is a cytotoxic compound derived from pyruvic acid. In E. coli, there are at least eight pathways that are responsible for the detoxification of methylglyoxal. The first reaction in this pathway is the reduction of pyruvaldehyde to (S)-lactaldehyde, along with the cofactor NADH, catalyzed by 2,5-diketo-D-gluconic acid reductase subunits A and B. Following this, (S)-lactaldehyde is dehydrogenated into L-lactic acid by the lactaldehyde dehydrogenase enzyme, also using NAD as a cofactor. Finally, L-lactic acid is converted to pyruvic acid by L-lactate dehydrogenase in a reaction involving the reduction of an electron acceptor. Pyruvic acid is then used in glycolysis and pyruvate dehydrogenase pathways.

Methylglyoxal, also known as pyruvaldehyde, is a cytotoxic compound derived from pyruvic acid. In E. coli, there are at least eight pathways that are responsible for the detoxification of methylglyoxal. The first reaction in this pathway is the reversible reduction of pyruvaldehyde to hydroxyacetone, along with the cofactor NADPH, catalyzed by an uncharacterized protein encoded by the yghZ gene, now known to be L-glyceraldehyde 3-phosphate reductase. Following this, hydroxyacetone is oxidized into (S)-propane-1,2-diol by the glycerol dehydrogenase enzyme, using NAD as a cofactor. Finally, (S)-propane-1,2-diol is transported into the periplasmic space.

Methylglyoxal, also known as pyruvaldehyde, is a cytotoxic compound derived from pyruvic acid. In E. coli, there are at least eight pathways that are responsible for the detoxification of methylglyoxal. The first reaction in this pathway is the reversible reduction of pyruvaldehyde to hydroxyacetone, along with the cofactor NADPH, catalyzed by an uncharacterized protein encoded by the yghZ gene, now known to be L-glyceraldehyde 3-phosphate reductase. Following this, hydroxyacetone is oxidized into (S)-propane-1,2-diol by the glycerol dehydrogenase enzyme, using NAD as a cofactor. Finally, (S)-propane-1,2-diol is transported into the periplasmic space.

The most common pathway for methylglyoxal detoxification is the glyoxalase system, which is composed of two enzymes that together convert methylglyoxal to (R)-lactate in the presence of glutathione. However, in E. coli, a single enzyme, glyoxalase III, catalyzes this conversion in a single step without involvement of glutathione. Activity of glyoxalase III increases at the transition to stationary phase and expression is dependent on RpoS, suggesting that this pathway may be important during stationary phase. (EcoCyc)

Methylglyoxal, also known as pyruvaldehyde, is a cytotoxic compound derived from pyruvic acid. In E. coli, there are at least eight pathways that are responsible for the detoxification of methylglyoxal. The first reaction in this pathway is the reduction of pyruvaldehyde to (S)-lactaldehyde, along with the cofactor NADH, catalyzed by 2,5-diketo-D-gluconic acid reductase subunits A and B. Following this, (S)-lactaldehyde is dehydrogenated into L-lactic acid by the lactaldehyde dehydrogenase enzyme, also using NAD as a cofactor. Finally, L-lactic acid is converted to pyruvic acid by L-lactate dehydrogenase in a reaction involving the reduction of an electron acceptor. Pyruvic acid is then used in glycolysis and pyruvate dehydrogenase pathways.

The most common pathway for methylglyoxal detoxification is the glyoxalase system, which is composed of two enzymes that together convert methylglyoxal to (R)-lactate in the presence of glutathione. However, in E. coli, a single enzyme, glyoxalase III, catalyzes this conversion in a single step without involvement of glutathione. Activity of glyoxalase III increases at the transition to stationary phase and expression is dependent on RpoS, suggesting that this pathway may be important during stationary phase. (EcoCyc)

L-lyxose is a sugar and a monosaccharide containing five carbon atoms and aldehyde group. Wild-type E.coli can't utilize L-lyxose as its source of carbon and energy. In mutated E.coli, it can metabolize l-lyxose through utilization of enzymes of the rhamnose, arabinose and 2,3-diketo-L-gulonate systems. β-L-lyxopyranose enter cell by L-rhamnose-proton symporter, then convert to l-xylulose by L-rhamnose isomerase. L-xylulose is further metabolized to L-xylulose-5-phosphate with energy ATP. Putative L-ribulose-5-phosphate 3-epimerase can convert L-xylulose -5-phosphate to L-ribulose 5-phosphate, and L-ribulose 5-phosphate 4-epimerase can catalyze L-ribulose 5-phosphate to xylulose 5-phosphate for further pentose phosphate.

The most common pathway for methylglyoxal detoxification is the glyoxalase system, which is composed of two enzymes that together convert methylglyoxal to (R)-lactate in the presence of glutathione. However, in E. coli, a single enzyme, glyoxalase III, catalyzes this conversion in a single step without involvement of glutathione. Activity of glyoxalase III increases at the transition to stationary phase and expression is dependent on RpoS, suggesting that this pathway may be important during stationary phase. (EcoCyc)

L-lyxose is a sugar and a monosaccharide containing five carbon atoms and aldehyde group. Wild-type E.coli can't utilize L-lyxose as its source of carbon and energy. In mutated E.coli, it can metabolize l-lyxose through utilization of enzymes of the rhamnose, arabinose and 2,3-diketo-L-gulonate systems. β-L-lyxopyranose enter cell by L-rhamnose-proton symporter, then convert to l-xylulose by L-rhamnose isomerase. L-xylulose is further metabolized to L-xylulose-5-phosphate with energy ATP. Putative L-ribulose-5-phosphate 3-epimerase can convert L-xylulose -5-phosphate to L-ribulose 5-phosphate, and L-ribulose 5-phosphate 4-epimerase can catalyze L-ribulose 5-phosphate to xylulose 5-phosphate for further pentose phosphate.