Properties of pancreatic zymogen granules studied by quasi-elastic light scattering.

Physico-chemical properties of isolated zymogen granules of the mouse pancreas were studied by means of quasi-elastic light scattering. The average diameter of the granules in 0.3 M sucrose was found to be 1.1 + or minus 0.1 micrometer from the correlation time of intensity fluctuation of the scattered light. The average diameter altered depending on the osmolality of the medium in a manner that the alteration was smaller than that expected from the van't Hoff relation. Aggregation of the granules induced by the increase of Ca2+ concentration or the decrease of pH in the medium was also detected. The aggregation started at a critical level of 1 mM CaCl2 or at pH 5.4.