SEPARATION AND ANALYSIS OF PIG PANCREATIC ZYMOGEN GRANULES WITH FREE-FLOW ELECTROPHORESIS AND LECTINS

Purified pig pancreatic zymogen granules were subjected to free now el ectrophoresis (FFE) in an acetate buffer system (acetic acid/NaOH, pH 5.5) to detect the presence or absence of more than one population or zymogen granules. Pig pancreatic zymogen granules were purified by dif ferential and density gradient centrifugation and subjected to FFE. Fr actions were analyzed for protein, alpha-amylase (EC 3.2.1.1) and 5'-n ucleotidase (EC 3.1.3.5) as marker enzymes for zymogen granule content and membranes, respectively. Only one distinct peak, with coincident alpha-amylase and 5'-nucleotidase activity, and most protein was detec ted, which reflects the presence of a single population of intact zymo gen granules. This was confirmed by electron microscopy. When the gran ules were incubated with different lectins before FFE, the one distinc t peak representing intact zymogen granules was shifted towards the ca thode in the case of concanavalin A (Con A) and Ricinus communis agglu tinin 120 (RCA 120). No splitting of the peak occurred. Our results do not support the hypothesis of a coexistence of more than one distinct population of zymogen granules.