Archaeosine synthase
Archaeosine synthase (EC 2.6.1.97, ArcS, TgtA2, MJ1022 (gene), glutamine:preQ0-tRNA amidinotransferase) is an enzyme with systematic name L-glutamine:7-cyano-7-carbaguanine aminotransferase. This enzyme catalyses the following chemical reaction

L-glutamine + 7-cyano-7-carbaguanine15 in tRNA + H2O 
  
    
      
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    {\displaystyle \rightleftharpoons }
   L-glutamate + archaeine15 in tRNAIn Euryarchaeota the reaction is catalysed by ArcS.

References
External links
Archaeosine+synthase at the U.S. National Library of Medicine Medical Subject Headings (MeSH)