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Lysosome membrane permeability to amines
C L Andrew1, A R Klemm, J B Lloyd
1Division of Developmental Biology, Jefferson Medical College, Alfred I. duPont Institute, Wilmington, DE 19899, USA.
Biochimica Et Biophysica Acta
|December 31, 1997
Summary
Rat liver lysosomes allow uncharged xenobiotic amines to cross their membranes. Permeability depends on hydrogen-bonding capacity, with charged nitrogen compounds unable to diffuse passively.
Area of Science:
- Biochemistry
- Cell Biology
- Pharmacology
Background:
- Lysosomes are key organelles in cellular waste disposal and drug metabolism.
- Understanding lysosomal permeability is crucial for xenobiotic compound delivery and efficacy.
Purpose of the Study:
- To investigate the permeability of rat liver lysosomes to xenobiotic organic compounds with nitrogen functions.
- To determine how molecular properties, such as charge and hydrogen-bonding capacity, influence lysosomal transport.
Main Methods:
- Utilized an osmotic-protection methodology to assess lysosomal membrane permeability.
- Incubated rat liver lysosomes in 250 mM sucrose across a pH range of 5 to 9 to confirm stability.
- Studied primary and tertiary amines with varying pKa values and functional groups at different pH levels.
Main Results:
- Rat liver lysosomes demonstrated stability between pH 5 and 9 for at least one hour.
- Uncharged amines were found to permeate the lysosome membrane.
- Molecular permeability correlated with total hydrogen-bonding capacity, with charged nitrogen compounds showing minimal passive diffusion.
Conclusions:
- Lysosomal permeability to xenobiotics is significantly influenced by the molecule's charge and hydrogen-bonding capacity.
- Uncharged amines can cross the lysosome membrane, while cationic compounds are largely restricted.
- Findings have implications for lysosome-targeted drug delivery and understanding xenobiotic metabolism within lysosomes.