In enzymology, a preQ1 synthase ( EC 1.7.1.13) is an enzyme that catalyzes the chemical reaction

7-aminomethyl-7-carbaguanine + 2 NADP⁺ ${\displaystyle \rightleftharpoons }$ 7-cyano-7-carbaguanine + 2 NADPH + 2 H⁺

Thus, the two substrates of this enzyme are 7-aminomethyl-7-carbaguanine and NADP⁺, whereas its 3 products are 7-cyano-7-carbaguanine, NADPH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on other nitrogenous compounds as donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 7-aminomethyl-7-carbaguanine:NADP+ oxidoreductase. Other names in common use include YkvM, QueF, preQ0 reductase, preQ0 oxidoreductase, 7-cyano-7-deazaguanine reductase, 7-aminomethyl-7-carbaguanine:NADP+ oxidoreductase, queuine synthase (incorrect as queuine is not the product), and queuine:NADP+ oxidoreductase (incorrect as queuine is not the product).

References

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• JA; Noguchi, S; Nishimura, S; Ohgi, T; Goto, T; Crain, PF; McCloskey, JA (1978). "Structure determination of a nucleoside Q precursor isolated from E. coli tRNA: 7-(aminomethyl)-7-deazaguanosine". Nucleic Acids Res. 5 (7): 2289–96. doi: 10.1093/nar/5.7.2289. PMC  342163. PMID  353740.
• Nishimura S; Yamaizumi, Z; Ohgi, T; Goto, T; Nishimura, Y; Hirota, Y; Nishimura, S (1978). "Isolation of Q nucleoside precursor present in tRNA of an E. coli mutant and its characterization as 7-(cyano)-7-deazaguanosine". Nucleic Acids Res. 5 (11): 4215–23. doi: 10.1093/nar/5.11.4215. PMC  342744. PMID  364423.
• Swairjo M.A.; Reddy R.R.; Lee B.; Van Lanen S.G.; Brown S.; de Crécy-Lagard V.; Iwata-Reuyl D, Schimmel P; preliminary X-ray characterization of the nitrile reductase QueF: a queuosine-biosynthesis enzyme (2005). "Crystallization". Acta Crystallogr. F. 61 (Pt 10): 945–8. doi: 10.1107/S1744309105029246. PMC  1991305. PMID  16511203.
• Chikwana, V.M.; Stec, B.; Lee, B.W.K.; de Crécy-Lagard, V.; Iwata-Reuyl, D.; Swairjo, M.A. (2012). "Structural basis of biological nitrile reduction". Journal of Biological Chemistry. 287 (36): 30560–70. doi: 10.1074/jbc.m112.388538. PMC  3436371. PMID  22787148.