title: 4-methyleneglutamine synthetase: a new amide synthetase present in germinating peanuts.
abstract: Enzymatic activity which catalyzes the synthesis of 4-methyleneglutamine from 4-methyleneglutamic acid + ammonia was detected in and partially purified from cotyledons of peanut seeds germinated 5 to 7 days. This activity was separated from glutamine and asparagine synthetases by ammonium sulfate precipitation and DEAE-cellulose chromatography. The enzyme is distinct from these other amide synthetases in its substrate specificity, lack of amide/hydroxylamine exchange, and use of ammonium ion as amide donor together with formation of AMP from ATP. The activity is quite labile in solution, but is retained as a precipitate in ammonium sulfate or when frozen in 12.5% glycerol at -77 degrees C. This activity might be responsible for catalyzing the rapid synthesis of 4-methyleneglutamine which occurs in germinating peanuts.
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D019732:Amide Synthases; D010367:Arachis; D002848:Chromatography, DEAE-Cellulose; D005971:Glutamates / Q000096:biosynthesis; D007700:Kinetics; D008025:Ligases / Q000032:analysis* / Q000378:metabolism; D010944:Plants / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D005971:Glutamates; C030977:4-methyleneglutamic acid; D000255:Adenosine Triphosphate; D008025:Ligases; D019732:Amide Synthases; C037658:4-methyleneglutamine synthetase