Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/38396
標題: Characterization of osmolyte betaine synthesizing sarcosine dimethylglycine N-methyltransferase from Methanohalophilus portucalensis
作者: Chen, S.Y.
賴美津
Lai, M.C.
Lai, S.J.
Lee, Y.C.
關鍵字: Compatible solutes;Betaine;Sarcosine dimethylglycine;N-methyltransferase;Methanogen;Archaea;glycine betaine;compatible solutes;halophilic methanogen;bacteria;osmoregulation;identification;transporter;principles;pathways
Project: Archives of Microbiology
期刊/報告no:: Archives of Microbiology, Volume 191, Issue 10, Page(s) 735-743.
摘要: 
To overcome the extracellular salt stress, Methanohalophilus portucalensis FDF1(T) synthesizes the compatible solute betaine through the methylation of glycine, sarcosine, and N,N-dimethylglycine. S-adenosylmethionine (AdoMet) is the methyl donor. The enzyme sarcosine dimethylglycine N-methyltransferase (SDMT) of M. portucalensis, that catalyzes the formation of N,N-dimethylglycine and glycine betaine, has been purified and characterized. SDMT, a monomer of 33 kDa with a pI at 5.03, has a narrow substrate specificity limited to using only sarcosine and dimethylglycine as substrates for the methyl transferase reaction. The K (m) values for sarcosine and AdoMet were 2.29 and 0.21 mM, respectively, with a V (max) of 0.83 mu mol/mg-min (k (cat) value of 0.44 s(-1)). The K (m) values for dimethylglycine and AdoMet were 3.76 and 0.59 mM, respectively, with a V (max) of 4.88 mu mol/mg-min (k (cat) of 2.68 s(-1)). A high concentration of the end product betaine (2.0 M) did not affect the SMT activity, but it slightly inhibited the DMT activity. Both activities were also not affected by potassium or sodium ions in concentrations of 200-1,000 mM. We compared this novel archaeal SDMT enzyme to other similar bacterial transferases as well as to the glycine sarcosine dimethylglycine methyltransferase found also in M. portucalensis.
URI: http://hdl.handle.net/11455/38396
ISSN: 0302-8933
DOI: 10.1007/s00203-009-0501-z
Appears in Collections:生命科學系所

Show full item record
 

Google ScholarTM

Check

Altmetric

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.