Section 7
Chapter 6,005

Nucleotide depleted f 1 atpase under conditions of steady state hydrolysis binds alpha phosphorus 32 atp only at the catalytic site

Mil'grom Y.M.; Murataliev, M.B.

Biologicheskie Membrany 3(10): 981-983


ISSN/ISBN: 0233-4755
Accession: 006004939

Under the conditions of the steady-state [.alpha.-32P]ATP hydrolysis by nucleotide-depleted F1-ATPase, over the substrate concentrations range from 0.1 to 300 .mu.M, one mole of [.alpha.-32P]nucleotide is bound per mole of F1-ATPase. Half-maximal [.alpha.-32P]nucleotide binding is observed at 20 nM of substrate. At all [.alpha.-32P]ATP concentrations used, the enzyme-bound nucleotide is rapidly chased by the unlabelled ATP. Consequently, this enzyme-nucleotide complex is the intermediate of the enzyme catalytic cycle. The non-exchangeable F1-ATPase nucleotide-binding sites are not loaded by nucleotides in the course of the steady-state [.alpha.-32P]ATP hydrolysis.

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