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Appl Environ Microbiol. 1997 Feb; 63(2): 414–419.
PMCID: PMC168333

An aminotransferase from Lactococcus lactis initiates conversion of amino acids to cheese flavor compounds.


The enzymatic degradation of amino acids in cheese is believed to generate aroma compounds and therefore to be involved in the complex process of cheese flavor development. In lactococci, transamination is the first step in the degradation of aromatic and branched-chain amino acids which are precursors of aroma compounds. Here, the major aromatic amino acid aminotransferase of a Lactococcus lactis subsp. cremoris strain was purified and characterized. The enzyme transaminates the aromatic amino acids, leucine, and methionine. It uses the ketoacids corresponding to these amino acids and alpha-ketoglutarate as amino group acceptors. In contrast to most bacterial aromatic aminotransferases, it does not act on aspartate and does not use oxaloacetate as second substrate. It is essential for the transformation of aromatic amino acids to flavor compounds. It is a pyridoxal 5'-phosphate-dependent enzyme and is composed of two identical subunits of 43.5 kDa. The activity of the enzyme is optimal between pH 6.5 and 8 and between 35 and 45 degrees C, but it is still active under cheese-ripening conditions.

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Selected References

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  • Alfano JR, Kahn ML. Isolation and characterization of a gene coding for a novel aspartate aminotransferase from Rhizobium meliloti. J Bacteriol. 1993 Jul;175(13):4186–4196. [PMC free article] [PubMed]
  • Alting AC, Engels W, van Schalkwijk S, Exterkate FA. Purification and Characterization of Cystathionine (beta)-Lyase from Lactococcus lactis subsp. cremoris B78 and Its Possible Role in Flavor Development in Cheese. Appl Environ Microbiol. 1995 Nov;61(11):4037–4042. [PMC free article] [PubMed]
  • Andreotti G, Cubellis MV, Nitti G, Sannia G, Mai X, Marino G, Adams MW. Characterization of aromatic aminotransferases from the hyperthermophilic archaeon Thermococcus litoralis. Eur J Biochem. 1994 Mar 1;220(2):543–549. [PubMed]
  • Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. [PubMed]
  • Engels D, Ndoricimpa J, Nahimana S, Gryseels B. Control of Schistosoma mansoni and intestinal helminths: 8-year follow-up of an urban school programme in Bujumbura, Burundi. Acta Trop. 1994 Nov;58(2):127–140. [PubMed]
  • Gelfand DH, Steinberg RA. Escherichia coli mutants deficient in the aspartate and aromatic amino acid aminotransferases. J Bacteriol. 1977 Apr;130(1):429–440. [PMC free article] [PubMed]
  • Godon JJ, Delorme C, Ehrlich SD, Renault P. Divergence of Genomic Sequences between Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris. Appl Environ Microbiol. 1992 Dec;58(12):4045–4047. [PMC free article] [PubMed]
  • Hayashi H, Wada H, Yoshimura T, Esaki N, Soda K. Recent topics in pyridoxal 5'-phosphate enzyme studies. Annu Rev Biochem. 1990;59:87–110. [PubMed]
  • Hayashi H, Inoue K, Nagata T, Kuramitsu S, Kagamiyama H. Escherichia coli aromatic amino acid aminotransferase: characterization and comparison with aspartate aminotransferase. Biochemistry. 1993 Nov 16;32(45):12229–12239. [PubMed]
  • Kirsch JF, Eichele G, Ford GC, Vincent MG, Jansonius JN, Gehring H, Christen P. Mechanism of action of aspartate aminotransferase proposed on the basis of its spatial structure. J Mol Biol. 1984 Apr 15;174(3):497–525. [PubMed]
  • Kittell BL, Helinski DR, Ditta GS. Aromatic aminotransferase activity and indoleacetic acid production in Rhizobium meliloti. J Bacteriol. 1989 Oct;171(10):5458–5466. [PMC free article] [PubMed]
  • Koga J, Syono K, Ichikawa T, Adachi T. Involvement of L-tryptophan aminotransferase in indole-3-acetic acid biosynthesis in Enterobacter cloacae. Biochim Biophys Acta. 1994 Dec 14;1209(2):241–247. [PubMed]
  • Kradolfer P, Niederberger P, Hütter R. Tryptophan degradation in Saccharomyces cerevisiae: characterization of two aromatic aminotransferases. Arch Microbiol. 1982 Dec 11;133(3):242–248. [PubMed]
  • Paris CG, Magasanik B. Purification and properties of aromatic amino acid aminotransferase from Klebsiella aerogenes. J Bacteriol. 1981 Jan;145(1):266–271. [PMC free article] [PubMed]
  • Pérez-Galdona R, Corzo J, León-Barrios MA, Gutiérrez-Navarro AM. Characterization of an aromatic amino acid aminotransferase from Rhizobium leguminosarum biovar trifolii. Biochimie. 1992 Jun;74(6):539–544. [PubMed]
  • Powell JT, Morrison JF. The purification and properties of the aspartate aminotransferase and aromatic-amino-acid aminotransferase from Escherichia coli. Eur J Biochem. 1978 Jun 15;87(2):391–400. [PubMed]
  • Schonbeck ND, Skalski M, Shafer JA. Reactions of pyrzdoxal 5'-phosphate, 6-aminocaproic acid, cysteine, and penicilamine. Models for reactions of Schiff base linkages in pyridoxal 5'-phosphate-requiring enymes. J Biol Chem. 1975 Jul 25;250(14):5343–5351. [PubMed]
  • Smid EJ, Konings WN. Relationship between utilization of proline and proline-containing peptides and growth of Lactococcus lactis. J Bacteriol. 1990 Sep;172(9):5286–5292. [PMC free article] [PubMed]
  • Sung MH, Tanizawa K, Tanaka H, Kuramitsu S, Kagamiyama H, Hirotsu K, Okamoto A, Higuchi T, Soda K. Thermostable aspartate aminotransferase from a thermophilic Bacillus species. Gene cloning, sequence determination, and preliminary x-ray characterization. J Biol Chem. 1991 Feb 5;266(4):2567–2572. [PubMed]
  • Toney MD, Kirsch JF. Lysine 258 in aspartate aminotransferase: enforcer of the Circe effect for amino acid substrates and general-base catalyst for the 1,3-prototropic shift. Biochemistry. 1993 Feb 16;32(6):1471–1479. [PubMed]
  • Trach KA, Hoch JA. Multisensory activation of the phosphorelay initiating sporulation in Bacillus subtilis: identification and sequence of the protein kinase of the alternate pathway. Mol Microbiol. 1993 Apr;8(1):69–79. [PubMed]
  • Whitaker RJ, Gaines CG, Jensen RA. A multispecific quintet of aromatic aminotransferases that overlap different biochemical pathways in Pseudomonas aeruginosa. J Biol Chem. 1982 Nov 25;257(22):13550–13556. [PubMed]
  • Xing RY, Whitman WB. Characterization of amino acid aminotransferases of Methanococcus aeolicus. J Bacteriol. 1992 Jan;174(2):541–548. [PMC free article] [PubMed]
  • Yano T, Mizuno T, Kagamiyama H. A hydrogen-bonding network modulating enzyme function: asparagine-194 and tyrosine-225 of Escherichia coli aspartate aminotransferase. Biochemistry. 1993 Feb 23;32(7):1810–1815. [PubMed]
  • Zappacosta F, Sannia G, Savoy LA, Marino G, Pucci P. Post-translational modifications in aspartate aminotransferase from Sulfolobus solfataricus. Detection of N-epsilon-methyllysines by mass spectrometry. Eur J Biochem. 1994 Jun 15;222(3):761–767. [PubMed]

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