Abstract
For F1-ATPases from mitochondria and chloroplasts, tight binding of Mg2+ and ADP without Pi at a catalytic site had been reported as a cause of enzyme inhibition. The time dependence of this inhibition and the effect of various agents on this process have been described (Du, Z., and Boyer, P. D. (1990) Biochemistry 29, 402-407, and references therein). Similar results are now reported for the ATPase from Halobacterium saccharovorum. The nonlinear hydrolysis kinetics were modulated by nitrate, azide, sulfite, GTP, ADP in the absence of ATP, or Pi in characteristic ways, in good analogy with the effects of these agents on F1 enzymes. The similarity to the F1 systems suggests that it is tight ADP binding that is affected. Although these reactions of the H. saccharovorum ATPase occurred on different time and concentration scales than those of F1-ATPases, the two systems do not appear to be fundamentally different. The hydrolytic mechanism of the H. saccharovorum ATPase thus identifies this enzyme as a member of the F0F1-ATPase family.
Highlights
For Fl-ATPases from mitochondriaand chloroplasts, ported before for other archaebacterialor V-type ATPases
1986;Boyer, 1989) suggested possible effecotfstightly saccharovorum ATPase identifies this enzyme as boundADPinthe H. saccharovorum system
Inhibition by GDP in thAe bsence of ATP-To compare the inhibitory effects of ADP and GDP under these conditions, the H. saccharovorum ATPase was incubated with 50 p~
Summary
For Fl-ATPases from mitochondriaand chloroplasts, ported before for other archaebacterialor V-type ATPases. After with Mn2+ alone (up to 3 mM) for 60 min, no inhibition of such incubations, the initial hydrolytic rate of F1-ATPases the ATPase could be detected (not shown).For Fl-ATPases, was low but recovered in the presence of ATP (Fitin et al, both metal and ADPwere necessary for the inhibitory effect 1979; Vasilyeva et al, 1982a; Vulfson et al, 1984; Guerrero et (Vasilyeva et al, 1980; Feldman and Boyer, 1985; Chernyak al., 1990).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
