Properties of kallikrein-containing granules isolated from the submaxillary gland of the guinea-pig.

1. Granular fractions of high purity consisting of subcellular kallikrein- and amylase-storing organelles have been isolated from homogenates of guinea-pig submaxillary gland.2. The isolated kallikrein- and amylase-containing granules closely resembled secretory granules observed in situ in serous acinar cells in intra-granular appearance, size and histochemical reaction.3. The subcellular, histochemical and ultrastructural studies indicate that the serine protease, kallikrein, is like amylase an exocrine enzyme with a functional role in saliva.