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Article: A study of H+ transport in gastric microsomal vesicles using fluorescent probes

TitleA study of H+ transport in gastric microsomal vesicles using fluorescent probes
Authors
Issue Date1978
Citation
Biochimica Et Biophysica Acta, 1978, v. 508 n. 2, p. 339-356 How to Cite?
AbstractFluorescent amines, 9-aminoacridine, acridine orange and quinacrine, were used as probes for a pH gradient (ΔpH) across gastric microsomal vesicles. Analysis of probe uptake data indicates that 9-aminoacridine distributes across the membrane as a weak base in accordance with the ΔpH. On the other hand, acridine orange and quinacrine show characteristics of binding to membrane sites in addition to accumulation in response to ΔpH. A discussion of the advantages and limitations of the probes is presented. Application of these probes to pig gastric microsomal vesicles indicates that the K +-stimulated ATPase is responsible for the transport of H + into the vesicles and thus develops a ΔpH across the membrane. The ΔpH generated by the K +-ATPase has a definite requirement for internal K +. The proton gradient can be discharged slowly after ATP depletion or rapidly either by detergent disruption of the vesicles or by increasing their leakiness using both H + and K + ionophores. On the other hand, the sole use of the K + ionophore, valinomycin, stimulates the ATP-induced formation of ΔpH by increasing the availability of K + to internal sites. This stimulation by valinomycin requires the presence of permeable anions like Cl -. Analysis of the Cl - requirement indicates that in the presence of valinomycin the net effect is the accumulation of HCl inside the gastric vesicles. With an external pH of 7.0, the ATP-generated ΔpH was calculated to be from 4 to 4.5 pH units. The results are consistent with the hypothesis that the K +-stimulated ATPase drives a K +/H + exchange across the gastric vesicles. Since other lines of evidence suggest that these gastric microsomes are derived from the tubulovesicular system of the oxyntic cell, the participation of the ATP-driven transport processes in gastric HCl secretion is of interest.
Persistent Identifierhttp://hdl.handle.net/10722/171467
ISSN
1999 Impact Factor: 2.59
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorLee, HCen_US
dc.contributor.authorForte, JGen_US
dc.date.accessioned2012-10-30T06:15:18Z-
dc.date.available2012-10-30T06:15:18Z-
dc.date.issued1978en_US
dc.identifier.citationBiochimica Et Biophysica Acta, 1978, v. 508 n. 2, p. 339-356en_US
dc.identifier.issn0006-3002en_US
dc.identifier.urihttp://hdl.handle.net/10722/171467-
dc.description.abstractFluorescent amines, 9-aminoacridine, acridine orange and quinacrine, were used as probes for a pH gradient (ΔpH) across gastric microsomal vesicles. Analysis of probe uptake data indicates that 9-aminoacridine distributes across the membrane as a weak base in accordance with the ΔpH. On the other hand, acridine orange and quinacrine show characteristics of binding to membrane sites in addition to accumulation in response to ΔpH. A discussion of the advantages and limitations of the probes is presented. Application of these probes to pig gastric microsomal vesicles indicates that the K +-stimulated ATPase is responsible for the transport of H + into the vesicles and thus develops a ΔpH across the membrane. The ΔpH generated by the K +-ATPase has a definite requirement for internal K +. The proton gradient can be discharged slowly after ATP depletion or rapidly either by detergent disruption of the vesicles or by increasing their leakiness using both H + and K + ionophores. On the other hand, the sole use of the K + ionophore, valinomycin, stimulates the ATP-induced formation of ΔpH by increasing the availability of K + to internal sites. This stimulation by valinomycin requires the presence of permeable anions like Cl -. Analysis of the Cl - requirement indicates that in the presence of valinomycin the net effect is the accumulation of HCl inside the gastric vesicles. With an external pH of 7.0, the ATP-generated ΔpH was calculated to be from 4 to 4.5 pH units. The results are consistent with the hypothesis that the K +-stimulated ATPase drives a K +/H + exchange across the gastric vesicles. Since other lines of evidence suggest that these gastric microsomes are derived from the tubulovesicular system of the oxyntic cell, the participation of the ATP-driven transport processes in gastric HCl secretion is of interest.en_US
dc.languageengen_US
dc.relation.ispartofBiochimica et Biophysica Actaen_US
dc.subject.meshAcridines - Metabolismen_US
dc.subject.meshAdenosine Triphosphatases - Metabolismen_US
dc.subject.meshAnimalsen_US
dc.subject.meshBiological Transporten_US
dc.subject.meshFluorescent Dyesen_US
dc.subject.meshGastric Mucosa - Physiologyen_US
dc.subject.meshHydrogen-Ion Concentrationen_US
dc.subject.meshMembranes - Physiologyen_US
dc.subject.meshMicrosomes - Physiologyen_US
dc.subject.meshPotassium - Metabolismen_US
dc.subject.meshQuinacrine - Metabolismen_US
dc.subject.meshSpectrometry, Fluorescenceen_US
dc.titleA study of H+ transport in gastric microsomal vesicles using fluorescent probesen_US
dc.typeArticleen_US
dc.identifier.emailLee, HC:leehc@hku.hken_US
dc.identifier.authorityLee, HC=rp00545en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1016/0005-2736(78)90336-X-
dc.identifier.pmid25082-
dc.identifier.scopuseid_2-s2.0-0017885019en_US
dc.identifier.volume508en_US
dc.identifier.issue2en_US
dc.identifier.spage339en_US
dc.identifier.epage356en_US
dc.identifier.isiWOS:A1978EW26000013-
dc.publisher.placeNetherlandsen_US
dc.identifier.scopusauthoridLee, HC=26642959100en_US
dc.identifier.scopusauthoridForte, JG=26425932500en_US

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