Electrophoresis of isolated secretory granules from guinea-pig submaxillary gland.

1 The nature of the surface charge on secretory granules from the submaxillary gland of the guinea-pig has been studied by electrophoresis of the isolated granules. The granules suspended in buffered sucrose solutions move to the anode.2 Divalent ions reduce the anodal movements of the granules. Calcium and magnesium neutralize the net surface charge of the granules. This result supports the hypothesis that the electrostatic surface charge which can be reduced by calcium ions may be a major factor in controlling the fusion of secretory granules to the cell membrane, before release by exocytosis.3 The mechanisms which couple membrane events with enzyme or hormone release from secretory glands are considered.