Catalytic properties of β subunit isolated from chloroplast coupling factor 1

✍ Scribed by A. N. Malyan; O. I. Vitseva

• Book ID: 104619683
• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 578 KB
• Volume: 30
• Category: Article
• ISSN: 0166-8595
• DOI: 10.1007/bf00042008

✦ Synopsis

The chloroplast coupling factor (CF~) was dissociated into subunits by the freezing-thawing procedure in the presence of 0.5 M NaBr and the/3 subunit was purified by ion-exchange chromatography on a DEAE-cellulose column. The/3 subunit did not catalyze ATP hydrolysis either in the presence or in the absence of reagents known to activate Mg2+-dependent ATPase activity of CF~. However, it manifested appreciable adenylate kinase-like and ATP-ADP y-phosphate exchange activities. The adenylate kinase-like activity only slightly depended on Mg 2+ ions. Ethanol, and especially diadenosine pentaphosphate, inhibited the reaction effectively. In contrast, the ATP-ADP exchange activity was 2+ Mg -dependent. Ethanol and diadenosine pentaphosphate were poor inhibitors. Sulfite, the CF~-ATPase activator, and quercetin, its inhibitor, had a minor effect on catalytic activity of the/3 subunit.