On the presence of starch bound phosphate in potato leaf starch

The presence of starch-bound phosphate in potato leaves collected late afternoon in the middle of July when the starch content is high (12.9% dry matter basis) was studied. Starch was extracted from the leaves with dimethylsulphoxide and fragments of starch were purified by ultrafiltration in two steps in combination with an alpha-amylase hydrolysis. The fragments were analysed with P-31-NMR and no signals corresponding to phosphate monoesters linked to glucose at the C-3 and/or C-6 positions were detected. The results show that starch in potato leaves does not contain any detectable amounts of phosphate monoesters. (c) 2004 Published by Elsevier Ltd.