Читать книгу Plant Nucleotide Metabolism - Hiroshi Ashihara - Страница 38

Nucleoside monophosphates are converted to nucleoside diphosphates by nucleoside-monophosphate kinase (EC 2.7.4.4) which catalyses reaction 1 as shown in Table 3.1. The substrate specificity of this enzyme is broad; many nucleoside monophosphates can act as acceptors and other nucleoside triphosphates can also serve as phosphate donors instead of ATP. However, the cellular concentration of ATP is usually much higher than that of other nucleoside triphosphates (Table 2.1), so ATP is the principal phosphate donor.

Table 3.1 Enzymes involved in the conversion of nucleoside mono-, di- and triphosphate in plants.

Enzymes	EC	Reaction	References
1	Nucleoside-monophosphate kinase	2.7.4.4	ATP + Nucleoside monophosphate → ADP + Nucleoside diphosphate	Noda (1962)
2	Nucleoside-diphosphate kinase	2.7.4.6	ADP + Nucleoside triphosphate → ATP + Nucleoside diphosphate	Dorion and Rivoal (2015)
3	Adenylate kinase (= Myokinase)	2.7.4.3	AMP + ATP → 2 ADP	Johansson et al. (2008)
4	Guanylate kinase	2.7.4.8	GMP + ATP → GDP + ADP	Nomura et al. (2014)
5	UMP/CMP kinase (= Cytidylate kinase)	2.7.4.14	CMP + ATP → CDP + ADP UMP + ATP → UDP + ADP	Zhou et al. (1998)
6	ATP synthase (H+-transporting two-sector ATPase)	3.6.3.14	ADP + Pi + H+out → ATP + H2O + H+in	Li et al. (2012)
7	Phosphoglycerate kinase	2.7.2.3	ADP + 3-Phospho-D-glyceroyl phosphate → ATP + 3-Phospho-D-glycerate	Troncoso-Ponce et al. (2012)
8	Pyruvate kinase	2.7.1.40	ADP + Phosphoenolpyruvate → ATP + Pyruvate	Baysdorfer and Bassham (1984)
9	Succinate – CoA ligase (ADP-forming)	6.2.1.5	ADP + Pi + Succinyl-CoA → ATP + Succinate + CoA	Johnson et al. (1998)