Use of Polyethylene Glycol in Isolation and Assay of Stable, Enzymically Active Starch Granules from Developing Wheat Endosperms

Antonius H. G. C. Rijven

$Division ofPlant Industry, Commonwealth Scientific and Industrial Research Organization, Box 1600, Canberra, A.C. T. 2601, Australia ABSTRACr A procedure using polyethylene glycol (PEG), moleculr weight 1000, was developed for the isoltion of starch grnules from wheat endosperm. Immature endosperm tiue was cut repeatedly in 300 nill lar PEG 1000 ad filtered through Micloth. Centrifugation separated a pellet from a supernatant with inhibitory activity. The pellet contained several enzyme activiti, inld soluble and bound components of starch synthase, sltrch phosphorylse, ad sucrose synthase activities. The starch phosphorylse activity was unaffected by several washin with 300 mil lar PEG 1000 but was lost when the grales were washed once withot PEG or washed with sucrose, glyceroL or sorbitol (up to 30%, w/v). The hfai of starch synthase, remaining on the granules after a wash without PEG (the 'bound' activity) was not affected by the additio of 30% sorbitol to the wash buffer. This fraction became larg with rain development (0.2-0.7). To obtain high activity, PEG was required not only during isolation of granules but also in the assay of both starch phosphorylase and starch synthim giving optimum activity at 225 to 255 millar. PEG reduced the requirement for glycogen as$

Use of Polyethylene Glycol in Isolation and Assay of Stable, Enzymically Active Starch Granules from Developing Wheat Endosperms

Antonius H. G. C. Rijven

Follow Plant Physiology , Volume 75 (2): 323 American Society of Plant Biologist – Jun 19, 1984