IUBMB Enzyme Nomenclature


Accepted name: phosphoglucan, water dikinase

Reaction: ATP + [phospho-α-glucan] + H2O = AMP + O-phospho-[phospho-α-glucan] + phosphate

Other name(s): PWD; OK1

Systematic name: ATP:phospho-α-glucan, water phosphotransferase

Comments: The enzyme phosphorylates granular starch that has previously been phosphorylated by EC, α-glucan, water dikinase; there is no activity with unphosphorylated glucans. It transfers the β-phosphate of ATP to the phosphoglucan, whereas the γ-phosphate is transferred to water [1]. In contrast to EC, which phosphorylates the glucose groups in glucans predominantly on the O-6 position, this enzyme phosphorylates glucose groups in phosphorylated starch predominantly on O-3 [2]. The protein phosphorylates itself with the β-phosphate of ATP, which is then transferred to the glucan [1].

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 912567-76-1


1. Kötting, O., Pusch, K., Tiessen, A., Geigenberger, P., Steup, M. and Ritte, G. Identification of a novel enzyme required for starch metabolism in Arabidopsis leaves. The phosphoglucan, water dikinase. Plant Physiol. 137 (2005) 242-252. [PMID: 15618411]

2. Ritte, G., Heydenreich, M., Mahlow, S., Haebel, S., Kötting, O. and Steup, M. Phosphorylation of C6- and C3-positions of glucosyl residues in starch is catalysed by distinct dikinases. FEBS Lett. 580 (2006) 4872-4876. [PMID: 16914145]

[EC created 2005]

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