Characterization of nucleotide binding sites of the isolated H(+)-ATPase from spinach chloroplasts, CF(0)F(1).
Arch Biochem Biophys
; 376(1): 141-8, 2000 Apr 01.
Article
in En
| MEDLINE
| ID: mdl-10729199
ABSTRACT
Soluble purified CF(0)F(1) from chloroplasts was either oxidized or reduced and then incubated with [alpha-(32)P]ATP in the presence or in the absence of Mg(2+). Depending on the conditions of incubation, the enzyme showed different tight-nucleotide binding sites. In the presence of EDTA, two sites bind [alpha-(32)P]ATP from the reaction medium at different rates. Both sites promote ATP hydrolysis, since equimolar amounts of [alpha-(32)P]ATP and [alpha-(32)P]ADP are bound to the enzyme. In the presence of Mg(2+), only one site appears during the first hour of incubation, with characteristics similar to those described in the absence of Mg(2+). However, after this time a third site appears also permitting binding of ATP from the reaction medium, but in this case the bound ATP is not hydrolyzed. Covalent derivatization by 2-azido-[alpha-(32)P]ATP was used to distinguish between catalytic and noncatalytic sites. In the presence of Mg(2+), there are at least three distinct nucleotide binding sites that bind nucleotide tightly from the reaction medium two of them are catalytic and one is noncatalytic.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Chloroplasts
/
Proton-Translocating ATPases
/
Spinacia oleracea
Language:
En
Journal:
Arch Biochem Biophys
Year:
2000
Document type:
Article
Affiliation country: