title: Enhancement of glutathione production by altering adenosine metabolism of Escherichia coli in a coupled ATP regeneration system with Saccharomyces cerevisiae.
abstract: OBJECTIVE
  Adenosine triphosphate (ATP) during the enzymatic production of glutathione is necessary. In this study, our aims were to investigate the reason for low glutathione production in Escherichia coli coupled with an ATP regeneration system and to develop a new strategy to improve the system.
  
  
  RESULTS
  Glutathione can be synthesized by enzymatic methods in the presence of ATP and three precursor amino acids (L-glutamic acid, L-cysteine and glycine). In this study, glutathione was produced from E. coli JM109 (pBV03) coupled with an ATP regeneration system, by using glycolytic pathway of Saccharomyces cerevisiae WSH2 as ATP regenerator from adenosine and glucose. In the coupled system, adenosine used for ATP regeneration by S. cerevisiae WSH2 was transformed into hypoxanthine irreversibly by E. coli JM109 (pBV03). As a consequence, S. cerevisiae WSH2 could not obtain enough adenosine for ATP regeneration in the glycolytic pathway in spite of consuming 400 mmol l(-1) glucose within 1 h. By adding adenosine deaminase inhibitor to block the metabolism from adenosine to hypoxanthine, glutathione production (8.92 mmol l(-1)) enhanced 2.74-fold in the coupled system.
  
  
  CONCLUSIONS
  This unusual phenomenon that adenosine was transformed into hypoxanthine irreversibly by E. coli JM109 (pBV03) revealed that less glutathione production in the coupled ATP regeneration system was because of the poor efficiency of ATP generation.
  
  
  CONCLUSIONS
  The results presented here provide a strategy to improve the efficiency of the coupled ATP regeneration system for enhancing glutathione production. The application potential can be microbial processes where ATP is needed.
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu, China.
authors.forename: X
authors.initials: X
authors.lastname: Liao
authors.forename: T
authors.initials: T
authors.lastname: Deng
authors.forename: Y
authors.initials: Y
authors.lastname: Zhu
authors.forename: G
authors.initials: G
authors.lastname: Du
authors.forename: J
authors.initials: J
authors.lastname: Chen
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000241:Adenosine / Q000378:metabolism*; D058892:Adenosine Deaminase Inhibitors; D000255:Adenosine Triphosphate / Q000096:biosynthesis / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology; D004926:Escherichia coli / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D005978:Glutathione / Q000032:analysis / Q000096:biosynthesis*; D006019:Glycolysis; D019271:Hypoxanthine / Q000378:metabolism; D007218:Industrial Microbiology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*
chemical_list: D058892:Adenosine Deaminase Inhibitors; D019271:Hypoxanthine; C040554:(2R,3S)-3-(4-Amino-1H-imidazo(4,5-c)pyridin-1-yl)-2-nonanol; D000255:Adenosine Triphosphate; D005978:Glutathione; D005947:Glucose; D000225:Adenine; D000241:Adenosine