Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.14 (ATP synthase)
 7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the kinetics of mitochondrial ATPase in bovine heart mitochondria and submitochondrial particles upon treatment with phospholipase A2, or upon addition of n-butanol to perturb the lipid protein interactions. The changes observed are the following: (1) Lipid removal or perturbation with butanol is accompanied by loss of ATPase activity with decrease of both V and of the KM for ATP. (2) There are changes of activation energy of ATPase activity at temperatures above the discontinuity normally observed for membrane-bound enzymes in mitochondria. In particular, butanol abolishes the discontinuity, and induces a constant activation energy of about 32 kcal/mol in the range 8--37 degrees C. (3) Butanol modifies the pH dependence of ATPase shifting the pH optimum from around 10 to less alkaline values. The optimum for Mg2+ concentrations is increased by the solvent. (4) Treatment with phospholipase A2 results in a removal of oligomycin-sensitive ATPase, whereas butanol addition prevents oligomycin inhibition of ATPase. (5) In beef heart mitochondria, a spin-labelled analog of the inhibitor, dicyclohexyl carbodiimide, did not show any change in environment upon butanol addition, unlike that found in mitochondria from Saccharomyces cerevisiae.
 ...
PMID:Lipid protein interactions in mitochondria. VII. A comparison of the effects of lipid removal and lipid perturbation of the kinetic properties of mitochondrial ATPase. 15 58

The dicyclohexylcarbodiimide (DCCD)-binding proteolipid of the chloroplast ATPase complex was solubilized in 1-butanol, isolated by ion exchange chromatography, and reconstituted in a liposomal system. Proton-conducting activity was monitored by fluorometry with 9-aminoacridine as an indicator of delta pH in K+-loaded liposomes suspended in a K+-free medium. Addition of valinomycin served to create a membrane potential. Proton mediation was further followed potentiometrically with a pH electrode. Reconstituted chloroplast DCCD-binding proteolipid rapidly catalyzed passive proton movement as measured by the quenching of 9-aminoacridine fluorescence upon addition of valinomycin to K+-loaded vesicles. Proton translocation was inhibited to approximately 80% by hydrophobic dicyclohexylcarbodiimide but not its water-soluble analog (1-ethyl-3[3-dimethylaminopropyl]carbodiimide). Maximal inhibition by DCCD occurred after 60 min of incubation with 20 to 40 nmol of DCCD/20 nmol of proteolipid/10 mumol of lipid. The velocity of proton conduction increased when the external proton concentration in the medium was increased. Similar data were obtained using a pH electrode to follow proton movement. Subjection of proteolipid liposomes to tetranitromethane, resulting in nitration of tyrosine, markedly reduced proton conduction (62% inhibition). In a similar fashion preincubation of reconstituted vesicles with hydrophobic phenylisothiocyanate at neutral pH resulted in a decreased rate of proton movement (50% inhibition) while hydrophilic p-sulfophenylisothiocyanate appeared to have no effect.
 ...
PMID:The proteolipid subunit of the chloroplast adenosine triphosphatase complex. Reconstitution and demonstration of proton-conductive properties. 644 55

When isolated cucumber (Cucumis sativus L.) mitochondria were treated with (14)C-labelled dicyclohexylcarbodiimide (DCCD), a single polypeptide was predominantly labelled. This polypeptide was soluble in 1-butanol or chloroform: methanol (2: 1, v/v) and had an apparent molecular mass of approximately 7 kDa; it therefore had the characteristic properties of the DCCD-binding proteolipid subunit of the ATP synthase complexes of mitochondria, chloroplasts, and prokaryotes.When isolated cucumber mitochondria were allowed to synthesize protein in the presence of [(35)S]methionine and then extracted with 1-butanol or chloroform: methanol (2: l, v/v), a (35)S-labelled proteolipid that migrated more rapidly on SDS-polyacrylamide gels than the pro-teolipid labelled by [(14)C]DCCD was solubilized. Treatment of mitochondria with unlabelled DCCD after they had been allowed to synthesize protein, specifically converted some of the [(35)S]methionine-labelled proteolipid to a form that comigrated with the [(14)C]DCCD-labelled proteolipid. We therefore conclude that a DCCD-binding proteolipid is synthesized by isolated cucumber mitochondria.
...
PMID:Synthesis of a dicyclohexylcarbodiimide-binding proteolipid by cucumber (Cucumis sativus L.) mitochondria. 2417 55