Use of the Flux Model of Amino Acid Metabolism of Escherichia coli

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A. V. Lyubetskaya^1*, L. I. Rubanov², and M. S. Gelfand^1,2

¹Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119992 Moscow, Russia; fax: (495) 939-3158; E-mail: lyubetsky.anna@mail.ru

²Institute for Information Transmission Problems, Russian Academy of Sciences, Bolshoi Karetnyi Pereulok 19, 127994 Moscow, Russia; fax: (495) 209-0579; E-mail: gelfand@iitp.ru; rubanov@iitp.ru

^* To whom correspondence should be addressed.

Received April 7, 2006; Revision received July 25, 2006

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A program implementing a flux model of Escherichia coli metabolism was used to analyze the effects of the addition of amino acids (tryptophan, tyrosine, phenylalanine, leucine, isoleucine, valine, histidine, lysine, threonine, cysteine, methionine, arginine, proline) to minimal medium or media lacking nitrogen, carbon, or both. The overall response of the metabolic system to the addition of various amino acids to the minimal medium is similar. Glycolysis and the synthesis of pyruvate with its subsequent degradation to acetate via acetyl-CoA become more efficient, whereas the fluxes through the pentose phosphate pathway and the TCA cycle decrease. If amino acids are used as the sole source of carbon, nitrogen, or both, the changes in the flux distribution are determined mainly by the carbon limitation. The phosphoenolpyruvate to glucose-6-phosphate flux increases; the flux through the pentose phosphate path is directed towards ribulose-5-phosphate. Other changes are determined by the compounds that are the primary products of catabolism of the added amino acid.

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KEY WORDS: flux balance analysis, Escherichia coli, metabolism of amino acids, metabolism modeling

DOI: 10.1134/S0006297906110113

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