Intracellular distribution of submaxillary kallikrein

1. Differential centrifugation and sucrose density‐gradient data indicate that kallikrein in the submaxillary gland is associated with particles which sediment with the nuclear and heavy mitochondrial fractions and equilibrate with 1·7‐1·8 M sucrose. 2. The sedimentation properties of the kallikrein containing particles differ from those of mitochondria and lysosomes, but resemble those of the pancreatic zymogen granules. 3. Histological observations indicate that kallikrein is associated with basophilic particles which stain positively with Periodic Acid‐Schiff reagent. 4. Pilocarpine causes a preferential secretion of kallikrein and amylase into saliva. 5. The results would support an exocrine role for submaxillary kallikrein.