Related Experiment Video
Updated: Aug 14, 2026

A Colorimetric Assay that Specifically Measures Granzyme B Proteolytic Activity: Hydrolysis of Boc-Ala-Ala-Asp-S-Bzl
Published on: November 28, 2014
Permeability of zymogen granule membrane to protein
Abstract:
The evidence that the membrane of the pancreatic zymogen granule is permeable to its contained secretory proteins is outlined. Included is a discussion of the nature and characteristics of the equilibrium-dependent release of protein from isolated granules, the evidence for the permeability of the granule membrane to digestive enzyme protein in situ, and the seeming paradox that isolated granules release protein in medium similar to that thought to exist in the cell. The permeability hypothesis is reconsidered here in light of recent claims of stable nonpermeable granules.
Related Concept Videos
Introduction to Membrane Proteins
Membrane Proteins
Single-pass Transmembrane Proteins
Protein Diffusion in the Membrane
GPI Anchoring of Proteins in the ER Membrane
GPI-anchor structure
A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
Multi-pass Transmembrane Proteins and β-barrels
α-Helix containing multi-pass transmembrane proteins
Multi-pass transmembrane proteins such as G-protein-linked receptors (GPCRs) and...

