Reaction: ATP + α-glucan + H2O = AMP + phospho-α-glucan + phosphate
Other name(s): starch-related R1 protein, GWD
Systematic name: ATP:α-glucan, water phosphotransferase
Comments: Requires Mg2+. ATP appears to be the only phosphate donor. No activity could be detected using GTP, UTP, phosphoenolpyruvate or diphosphate . The protein phosphorylates glucans exclusively at the O-6 position of glucosyl residues . The protein phosphorylates itself with the β-phosphate of ATP, which is then transferred to the glucan .
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 664327-94-0
1. Ritte, G., Lloyd, J.R., Eckermann, N., Rottmann, A., Kossmann, J. and Steup, M. The starch-related R1 protein is an α-glucan, water dikinase. Proc. Natl. Acad. Sci. USA 99 (2002) 7166-7171. [PMID: 12011472]
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]