Pre-steady-state properties of bovine heart mitochondrial ATPase: a nucleotide-dependent H+ burst.
The transient kinetics of bovine heart mitochondrial ATPase (F1) depleted of loosely bound nucleotides were observed. The activation process which was shown as a lag time before steady-state hydrolysis observed previously (Clark et al. (1984) Arch. Biochem. Biophys. 233, 378-392) was preceded by a proton burst when F1 was stripped of its loose nucleotides. 5'-Adenylylimidodiphosphate (Ado PP[NH]P) or MgATP binding is shown to cause proton release. maximum proton release per F1 free of loosely bound nucleotides is observed with MgATP. Modification with NBD-CL of F1 that was nucleotide-depleted eliminated the proton burst, which suggests that the modified tyrosine (i.e., in the catalytic subunit) is directly involved in the release of protons.
Daggett
S G
SG
Schuster
S M
SM
D009327:4-Chloro-7-nitrobenzofurazan / Q000494:pharmacology; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000266:Adenylyl Imidodiphosphate / Q000378:metabolism; D000818:Animals; D002417:Cattle; D066298:In Vitro Techniques; D007700:Kinetics; D009206:Myocardium / Q000201:enzymology*; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D011522:Protons
D011522:Protons; D000266:Adenylyl Imidodiphosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D009327:4-Chloro-7-nitrobenzofurazan