Unknown

Dataset Information

0

Isolation of ATPase I, the proton pump of chromaffin-granule membranes.


ABSTRACT: Chromaffin-granule membranes contain two ATPases, which can be separated by (NH4)2SO4 fractionation after solubilization with detergents, or by phase segregation in Triton X-114. ATPase I (Mr 400000) is inhibited by trialkyltin, quercetin and alkylating agents, and hydrolyses both ATP and ITP. It contains up to five types of subunit, including a low-Mr hydrophobic polypeptide that reacts with dicyclohexylcarbodi-imide; these subunits are unrelated to those of mitochondrial F1F0-ATPase, as judged by size and reaction with antibodies. ATPase II (Mr 140000) is inhibited by vanadate, and is specific for ATP; it has not been extensively purified. Proton translocation by resealed chromaffin-granule 'ghosts', measured by uptake of methylamine or by quenching of the fluorescence of 9-amino-6-chloro-2-methoxyacridine, is supported by the hydrolysis of ATP or ITP, and inhibited by quercetin or alkylating agents, but not by vanadate. ATPase I must therefore be the proton translocator involved in the uptake of catecholamines and possibly of other components of the chromaffin-granule matrix, whereas ATPase II does not translocate protons.

PROVIDER: S-EPMC1152787 | BioStudies | 1985-01-01

REPOSITORIES: biostudies

Similar Datasets

1983-01-01 | S-EPMC1154210 | BioStudies
1986-01-01 | S-EPMC1147499 | BioStudies
1989-01-01 | S-EPMC1138389 | BioStudies
1984-01-01 | S-EPMC1144022 | BioStudies
| S-EPMC135828 | BioStudies
1991-01-01 | S-EPMC1150202 | BioStudies
1990-01-01 | S-EPMC1149522 | BioStudies
1979-01-01 | S-EPMC1161097 | BioStudies
1982-01-01 | S-EPMC1158328 | BioStudies
1986-01-01 | S-EPMC1147241 | BioStudies