1.7.1.13	2-amino-5-cyanopyrrolo[2,3-d]pyrimidin-4-one + 2 NADPH + 2 H+	natural substrate	
1.7.1.13	7-cyano-7-deazaguanine + 2 NADPH + 2 H+	late step in biosynthesis of the modified tRNA nucleoside queuosine	
1.7.1.13	7-cyano-7-deazaguanine + 2 NADPH + 2 H+	i.e. preQ0