Abstract.
For quantification of α-glucan, water dikinase (GWD) activity in crude extracts of plant tissues a radio-labeling assay was established that uses soluble starch and 33P-labeled ATP as phosphate acceptor and donor, respectively. A constant rate of starch labeling was observed only if the ATP applied was labeled at the β position. In wild-type extracts from leaves of Arabidopsis thaliana (L.) Heynh. the maximum rate of starch phosphorylation was approximately 27 pmol min–1 (mg protein)–1. Leaf extracts from the GWD-deficient sex1 mutants of Arabidopsis showed no significant incorporation of phosphate whereas extracts from potato (Solanum tuberosum L.) tuber expressing a GWD antisense construct exhibited less activity than the wild-type control. To our knowledge this is the first time that a quantification of the starch-phosphorylating activity has been achieved in plant crude extracts.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Electronic Publication
Rights and permissions
About this article
Cite this article
Ritte, G., Steup, M., Kossmann, J. et al. Determination of the starch-phosphorylating enzyme activity in plant extracts. Planta 216, 798–801 (2003). https://doi.org/10.1007/s00425-002-0931-1
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s00425-002-0931-1