IUBMB Enzyme Nomenclature

EC 6.3.5.7

Accepted name: glutaminyl-tRNA synthase (glutamine-hydrolysing)

Reaction: ATP + L-glutamyl-tRNAGln + L-glutamine = ADP + phosphate + L-glutaminyl-tRNAGln + L-glutamate

Other name(s): Glu-AdT; Glu-tRNAGln amidotransferase; glutamyl-tRNAGln amidotransferase; Glu-tRNAGln:L-glutamine amido-ligase (ADP-forming)

Systematic name: L-glutamyl-tRNAGln:L-glutamine amido-ligase (ADP-forming)

Comments: In systems lacking discernible glutamine—tRNA ligase (EC 6.1.1.18), glutamyl-tRNAGln is formed by a two-enzyme system. In the first step, a nondiscriminating ligase (EC 6.1.1.24, glutamate—tRNAGln ligase) mischarges tRNAGln with glutamate, forming glutamyl-tRNAGln. The glutamyl-tRNAGln is not used in protein synthesis until the present enzyme converts it into glutaminyl-tRNAGln (glutamyl-tRNAGlu is not a substrate for this reaction). Ammonia or asparagine can substitute for the preferred substrate glutamine.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 52232-48-1

References:

1. Horiuchi, K.Y., Harpel, M.R., Shen, L., Luo, Y., Rogers, K.C. and Copeland, R.A. Mechanistic studies of reaction coupling in Glu-tRNAGln amidotransferase. Biochemistry 40 (2001) 6450-6457. [PMID: 11371208]

2. Curnow, A.W., Tumbula, D.L., Pelaschier, J.T., Min, B. and Söll, D. Glutamyl-tRNAGln amidotransferase in Deinococcus radiodurans may be confined to asparagine biosynthesis. Proc. Natl. Acad. Sci. USA 95 (1998) 12838-12843. [PMID: 9789001]

3. Ibba, M. and Söll, D. Aminoacyl-tRNA synthesis. Annu. Rev. Biochem. 69 (2000) 617-650. [PMID: 10966471]

[EC 6.3.5.7 created 2002]


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