Involvement of a non‐proton pump factor (possibly Donnan‐type equilibrium) in maintenance of an acidic pH in lysosomes
Open Access
- 4 May 1992
- journal article
- Published by Wiley in FEBS Letters
- Vol. 302 (1) , 18-20
- https://doi.org/10.1016/0014-5793(92)80274-k
Abstract
Change of the internal pH of isolated lysosomes was measured with fluorescein isothiocyanate‐dextran. In buffer of pH 7.0, isolated lysosomes had an acidic pH of about 5.5, which decreased to pH 5.2 on addition of ATP. Addition of bafilomycin inhibited the acidification by H+‐ATPase and resulted in an increase of the internal pH to 5.5 due to passive diffusion of protons across the lysosomal membrane. However, no further alkalization was observed. The acidic pH (pH 5.5) of isolated lysosomes could be maintained for at least 48 h in the absence of ATP, but increased gradually to pH 5.9–6.4 upon incubation with monovalent cations (K+ or Na+), amines, or ionophores. These results suggest that a non‐proton pump factor (possibly Donnan equilibrium) is involved in maintaining the acidic pH of isolated lysosomes.Keywords
This publication has 12 references indexed in Scilit:
- Lysosomal H+-translocating ATPase has a similar subunit structure to chromaffin granule H+-ATPase complexBiochimica et Biophysica Acta (BBA) - Biomembranes, 1989
- Bafilomycins: a class of inhibitors of membrane ATPases from microorganisms, animal cells, and plant cells.Proceedings of the National Academy of Sciences, 1988
- Potassium ion dependent proton efflux and depolarization from spleen lysosomesBiochemical and Biophysical Research Communications, 1988
- Internal anion binding site and membrane potential dominate the regulation of proton pumping by the chromaffin granule ATPaseBiochemical and Biophysical Research Communications, 1987
- Bioenergetics of secretory vesiclesBiochimica et Biophysica Acta (BBA) - Reviews on Bioenergetics, 1986
- Identification and characterization of a proton pump on lysosomes by fluorescein-isothiocyanate-dextran fluorescence.Proceedings of the National Academy of Sciences, 1982
- The permeability properties of the lysosomal membraneBiochimica et Biophysica Acta (BBA) - Reviews on Biomembranes, 1977
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976
- A thermally induced alteration in lysosome membranes: Salt permeability at 0 and 37 °CBiochimica et Biophysica Acta (BBA) - Biomembranes, 1975
- Isolation and characterization of acidic lipoprotein in renal and hepatic lysosomesLife Sciences, 1970