TABLE 1.

Enzymes synthesizing dinucleoside polyphosphates.

Enzyme	Sourcea	Productsb	References
Aminoacyl-tRNA synthetases	Eukaryotes, prokaryotes	Ap3–5N, dAp4dA, Ap3Gp2	Goerlich et al., 1982; Brevet et al., 1989; Guo et al., 2009
Firefly luciferase	Photinus pyralis	Ap3–5N, Ap3–5dN, Gp4G	Guranowski et al., 1990; Sillero and Sillero, 2000
DNA ligase	T4 phage, Homo sapiens (Lig3)	Ap3A, Ap4A, Ap4G, Ap4dA	Madrid et al., 1998; McLennan, 2000; Sillero and Sillero, 2000
RNA ligase	T4 phage	Ap4A, Ap4G, Ap4dG, Ap4C, Ap4dC, Ap3A	Atencia et al., 1999; Sillero and Sillero, 2000
Acyl-coenzyme A synthetase	P. fragi	Ap4–6A, Ap4N	Fontes et al., 1998
4-coumarate: coenzyme A ligase	A. thaliana	Ap4A, Ap5A, dAp4dA	Pietrowska-Borek et al., 2003
UTP:glucose-1-phosphate uridylyl transferase	S. cerevisiae	Up4N, Up5A, Up5G	Guranowski et al., 2004
Ap4A phosphorylase	S. cerevisiae	Ap4N, Ap4dA	Brevet et al., 1987; Guranowski et al., 1988
GTP:GTP guanylyltransferase	A. franciscana	Gp4G, Gp4A, Gp3G, Gp3A	Liu and McLennan, 1994
GTP:mRNA guanylyltransferase	S. cerevisiae	Gp4N, Gp3N	Wang and Shatkin, 1984
Non-ribosomal peptide synthetase	B. brevis, E. coli	Ap4A, Ap5A, Ap6A	Dieckmann et al., 2001; Sikora et al., 2009
Ubiquitin, SUMO and NEDD8-activating enzymes	H. sapiens	Ap4A, Ap3A	Götz et al., 2019
Vascular endothelial growth factor receptor 2	H. sapiens	Ap2A, Ap4A, Ap6A, Ap3G, Ap4U, Gp2G, Up4U	Jankowski et al., 2013
Reverse transcriptase	HIV type 1	Ap3ddA, Ap4ddA, Gp4ddAc	Smith et al., 2005

^aOrthologous activities may also be present in related organisms. ^bExamples of products that have been detected; the list is not exhaustive and may vary with source of enzyme; only products likely to occur naturally are shown. ^cAlthough dideoxynucleotides are not natural, their formation indicates the potential for natural dinucleotide synthesis by reverse transcriptases.