The Escherichia coli yjfP Gene Encodes a Carboxylesterase Involved in Sugar Utilization during Diauxie

Abstract

Background: Acetylation and efflux of carbohydrates during cellular metabolism is a well-described phenomenon associated with a detoxification process to prevent metabolic congestion. It is still unclear why cells discard important metabolizable energy sources in the form of acetylated compounds. Methods: We describe the purification and characterization of an approximately 28-kDa intracellular carboxylesterase (YjfP) and the analysis of gene and protein expression by qRT-PCR and Western blot. Results: qRT-PCR and Western blot, respectively, showed that yjfP is upregulated during the diauxic lag in cells growing with a mixture of glucose and lactose. The β-galactosidase activity in the ΔyjfP strain was both delayed and half the magnitude of that of the wild-type strain. YjfP-hyperproducing strains displayed a long lag phase when cultured with glucose and then challenged to grow with lactose or galactose as the sole carbon source. Conclusion: Our results suggest that YjfP controls the intracellular concentration of acetyl sugars by redirecting them to the main metabolic circuits. Instead of detoxification, we propose that sugar acetylation is utilized by the cell for protection and to prevent the metabolism of a necessary minimal intracellular sugar pool. Those sugars can eventually be exported as a side effect of these mechanisms.

pH-dependent spontaneous hydrolysis rather than gut bacterial metabolism reduces levels of the ADHD treatment, Methylphenidate

“…Indeed, bacterial esterases that are able to hydrolyze carboxyl esters have been previously described [18]. For example, the highly abundant gut bacterium Escherichia coli harbors the esterase yjfP, which is able to hydrolyze the ester 4-nitrophenylacetate [19]. Similarly, Bacillus subtilis pnbA esterase has been shown to hydrolyze 4-nitrophenylacetate [20].…”

Stability of Methylphenidate under Various pH Conditions in the Presence or Absence of Gut Microbiota

“…Indeed, bacterial esterases that can hydrolyze carboxyl esters have been previously described [ 14 ]. For example, the highly abundant gut bacterium Escherichia coli harbors the esterase yjfP, which was shown to hydrolyze the ester 4-nitrophenylacetate [ 15 ]. Similarly, Bacillus subtilis pnbA esterase has been shown to hydrolyze 4-nitrophenylacetate [ 16 ].…”