title: Characterization of theanine-forming enzyme from Methylovorus mays no. 9 in respect to utilization of theanine production.
abstract: For development of theanine production from glutamic acid and ethylamine by coupling yeast sugar fermentation as an ATP-regenerating system, several strains were selected from among about 200 methylamine- and/or methanol-assimilating bacteria depending on the theanine-forming activity of their permeated cells. The amount of theanine formed by the cells of the selected strains was much larger than that by the cells of Escherichia coli AD494 (DE3) expressing Pseudomonas taetrolens Y-30 glutamine synthetase (GS), which has been found to be a usable enzyme for theanine production. A GS-like enzyme responsible for the theanine-forming reaction was obtained from an obligate methylotroph isolate, Methylovorus mays No. 9. The enzyme was induced by methylamine in the culture medium. A molecular mass of 410-470 kDa was obtained by gel filtration of the enzyme, and 51 kDa by SDS-PAGE analysis. The enzyme showed high activity toward methylamine rather than ammonia, which indicates that it is similar to known gamma-glutamylmethylamide synthetase. The isolated enzyme also had high reactivity to ethylamine in a neutral pH range, and formed theanine from glutamic acid and ethylamine in a reaction mixture containing a yeast sugar fermentation system for ATP-regeneration.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Shiga, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Mamoru
authors.initials: M
authors.lastname: Wakayama
authors.forename: Takashi
authors.initials: T
authors.lastname: Tachiki
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000645:Ammonium Sulfate; D002413:Cations, Divalent / Q000378:metabolism; D002463:Cell Membrane Permeability; D002848:Chromatography, DEAE-Cellulose; D003470:Culture Media; D004269:DNA, Bacterial / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004735:Energy Transfer; D005021:Ethylamines / Q000378:metabolism; D005285:Fermentation; D005971:Glutamates / Q000096:biosynthesis*; D018698:Glutamic Acid / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D017013:Methanobacteriaceae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D002413:Cations, Divalent; D003470:Culture Media; D004269:DNA, Bacterial; D005021:Ethylamines; D005971:Glutamates; D007202:Indicators and Reagents; D018698:Glutamic Acid; C026166:theanine; D000255:Adenosine Triphosphate; D000645:Ammonium Sulfate; C041564:ethylamine