Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Submitochondrial Particles”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,675 records · Page 93Linked to original sources
PubMed1988

Inhibition of vacuolar H+-ATPases by fusidic acid and suramin.

The vacuolar system of eukaryotic cells is energized by a few ATP-driven ion pumps. One of these, the H+-ATPase, plays a major role in providing the protonmotive force for several organelles, as well as maintaining the proper pH inside the organelles. Formation of the protonmotive force in organelles isolated from the vacuolar system was inhibited by fusidic acid. The inhibition results from a combination of uncoupling the proton pumping and inhibition of the H+-ATPase activity. Suramin is also a potent inhibitor of the H+-ATPase from chromaffin granules. A possible connection between these activities and inhibition of HIV infection is pointed out.

Animals↗
PubMed1988

The in vitro insertion of monoamine oxidase B into mitochondrial outer membranes.

Bovine monoamine oxidase (MAO) B has been synthesized in vitro using a reticulocyte lysate translation system directed by bovine liver poly(A)+ RNA. The newly synthesized enzyme apparently lacks a cleavable N-terminal extension, but MAO B is readily incorporated into mitochondria or isolated mitochondrial outer membranes prepared from rat liver. ATP is not required for the binding of the newly synthesized enzyme to the outer membranes, but is necessary for the insertion of MAO B into these membrane vesicles. The ATP is not required to generate a mitochondrial membrane potential as assembly occurs under conditions that preclude either the formation or the maintenance of the potential. MAO B will bind to but not become incorporated into outer membrane vesicles which have been treated with trypsin, suggesting that the insertion of MAO B also depends on protein factors present on the outer membranes.

Animals↗
PubMed1989

Structure of the ATP-synthase studied by electron microscopy and image processing.

The structure of ATP synthase from beef heart mitochondria has been studied by electron microscopy and image processing using negatively stained specimens of detergent-solubilized and membrane-bound molecules. The F1-ATPase and the membrane-embedded F0 sector of ATP synthase are found to be connected by a narrow stalk, 4-4.5 nm long and 3-3.5 nm wide, projecting about 4.2 nm from the membrane surface. The F0 sector has a globular shape, 6-8 nm in diameter and, in part, extends from the membrane lipid bilayer.

Animals↗
PubMed1990

The gamma subunit of F1 and the PVP protein of F0 (F0I) are components of the gate of the mitochondrial F0F1 H(+)-ATP synthase.

The gamma subunit of the F1 moiety of the bovine mitochondrial H(+)-ATP synthase is shown to function as a component of the gate. Addition of purified gamma subunit to F0-liposomes inhibits transmembrane proton conduction. This inhibition can be removed by the bifunctional thiol reagent diamide. Immunoblot analysis shows that the diamide effect is likely due to disulphide bridging of the gamma subunit with the PVP protein of the F0 sector.

Animals↗
PubMed1990

A mitochondrial protein fraction catalyzing transport of the K+ analog T1+.

A protein fraction has been obtained from detergent-solubilized mitochondrial membranes by its affinity for quinine, an inhibitor of K+ transport. A peptide derived from the predominant 53 kDa protein in this fraction is found to be identical in sequence to a portion of aldehyde dehydrogenase. Antigenically unrelated bands at 97, 77, 57, and 31 kDa are also seen on polyacrylamide gels. Observations utilizing a fluorescent probe entrapped in the lumen of membrane vesicles indicate that the reconstituted protein fraction imparts permeability to the K+ analog Tl+. These and other findings suggest that the affinity purified fraction includes a cation transport catalyst.

Aldehyde Dehydrogenase↗
PubMed1990

Carnitine palmitoyltransferase (CPT2) from liver mitochondrial inner membrane becomes inhibitable by malonyl-CoA if reconstituted with outer membrane malonyl-CoA binding protein.

A soluble extract was obtained on treatment of rat liver mitochondrial outer membranes with cholate which bound [14C]malonyl-CoA but was essentially free of carnitine palmitoyltransferase (CPT) activity. Extraction of mitochondrial inner membranes with cholate readily solubilized a CPT activity which was insensitive to malonyl-CoA. Combination of these two extracts caused the CPT derived from inner membranes to become inhibitable by malonyl-CoA.

Acyl Coenzyme A↗
PubMed1991

A 28 kDa mitochondrial protein is radiolabelled by crosslinking with a 125I-labelled presequence.

A 13-residue peptide containing the first 12 amino acids of the N-terminal part of the signal sequence of yeast cytochrome c oxidase subunit IV is shown by chemical crosslinking to interact with a mitochondrial protein. This result is obtained with mitochondria from four different origins. Submitochondrial localization experiments suggest that the 28 kDa labelled component is present on the outer face of the inner membrane. Since such addressing peptides are imported into mitochondria through the same machinery as protein precursors, the 28 kDa protein might be a component of the translocation apparatus.

Amino Acid Sequence↗
PubMed1991

Location of dinucleoside triphosphatase in the matrix space of rat liver mitochondria.

The submitochondrial location of dinucleoside triphosphatase (EC 3.6.1.29), previously shown to be in part associated with mitochondria, has been studied in rat liver. The precipitability and latency of activity in organelle suspensions, and the profile of solubilization by digitonin, were like those of the matrix space marker glutamate dehydrogenase, and differed from those of other submitochondrial fractions. This, and the synthesis of diadenosine polyphosphates by mitochondrial aminoacyl-tRNA synthetases, suggest the occurrence of a pathway for the intramitochondrial turnover of diadenosine 5',5'''-P1,P3-triphosphate (Ap3A).

Acid Anhydride Hydrolases↗
PubMed1991

Effects of the membrane potential upon the Ca(2+)- and cumene hydroperoxide-induced permeabilization of the inner mitochondrial membrane.

A protonophore-induced delta psi decrease in a 180-140 mV range causes an increase in the lag-period of Ca(2+)-induced mitochondrial permeabilization but has little effect on the cumene hydroperoxide-induced permeability transition of mitochondria. Suppression of the non-specific permeability induction seems to be mediated by an increase in [ADP] in the mitochondrial matrix. A further decrease in delta psi leads to additional suppression of the non-specific permeability as a result of a partial ruthenium red-sensitive efflux of the previously accumulated Ca2+. On the other hand, complete dissipation of delta psi causes immediate induction of the non-specific permeability. It is concluded that only complete dissipation of delta psi caused by H+ leakages may act as a trigger for non-specific permeability induction.

Animals↗
PubMed1993

A constitutive form of heat-shock protein 70 is located in the outer membranes of mitochondria from rat liver.

HSP73, the constitutive form of heat-shock protein 70, has been implicated in the translocation of preproteins across the mitochondrial membranes, being required for maintaining mitochondrial preproteins in an import competent conformation. Here we report that highly purified mitochondrial outer membranes contain a protein indistinguishable from HSP73 as a tightly associated peripheral component of the membrane. This membrane form of HSP73 was photolabelled with [alpha-32P]ATP and could be released from the outer membrane with sodium carbonate, but not after incubation of the membranes with salt or with ATP. A sensitive immunoassay with an anti-HSP73 monoclonal antibody, revealed the association of HSP73 with mitochondrial outer membrane vesicles at a level similar to that of preprotein import receptors.

Adenosine Triphosphate↗
PubMed1993

Effect of neutral and acidic phospholipids on mitochondrial ATP synthase secondary structure.

The secondary structure of delipidated and egg phosphatidylcholine or asolectin reconstituted mitochondrial ATP synthase complex from beef heart was investigated by Fourier transform infrared spectroscopy. Upon reconstitution, the infrared spectra of ATP synthase revealed an increase in turns and a concomitant decrease in beta-sheet content which occurred to a larger extent in the presence of asolectin rather than in the presence of egg phosphatidylcholine. These data correlate with kinetic data showing a higher ATPase activity of the asolectin reconstituted enzyme protein than the egg phosphatidylcholine reconstituted or delipidated enzyme complexes.

Animals↗
PubMed1995

Identification and purification of a bovine liver mitochondrial NAD(+)-glycohydrolase.

Nonenzymatic ADP-ribosylation of mitochondrial proteins is thought to play a role in the regulation of Ca2+ efflux from mitochondria. It has been shown that intramitochondrial ADP-ribose is generated by a specific NAD(+)glycohydrolase, which catalizes hydrolysis of NAD+ to ADP-ribose and nicotinamide. We purified this enzyme from bovine liver mitochondrial membranes. The final preparation had a 1660-fold purified enzyme activity and contained a main protein band with an apparent molar mass of 32,000 in a SDS-polyacrylamide gel. The identity of this protein band with NAD(+)-glycohydrolase was verified by renaturation of its enzymatic activity. Partial amino acid sequence information was obtained from two enzyme fragments after proteolytic cleavage of the protein band in the SDS-polyacrylamide gel. Searches in protein databases revealed that an arginine ADP-ribosyl hydrolase harbours two stretches of amino acids that are highly similar to the partial NAD(+)-glycohydrolase sequences.

Amino Acid Sequence↗
PubMed1985

The effect of glucagon on N-acetylglutamate-synthetase.

The effect of glucagon and the protein content of the diet on the activity of N-acetylglutamate synthetase was studied. The activity of N-acetylglutamate synthetase depended on the protein content of the diet. Glucagon increased the activity of N-acetylglutamate synthetase and reduced the stimulatory effect of arginine. The enzyme of glucose-fed animals became arginine independent. It was concluded that glucagon induced some kind of covalent modification of the synthetase.

Acetyltransferases↗
PubMed1987

Reversible association of ox liver glutamate dehydrogenase with the inner mitochondrial membrane.

A comparative study on the catalytic and allosteric properties of particulate and soluble forms of ox liver glutamate dehydrogenase has been carried out. The response of the bound enzyme to release by various effectors was investigated. The particulate enzyme was found to have catalytic activities similar to the free enzyme in contrast to its behaviour when bound to pure anionic phospholipids. Possible reasons for such outstanding differences are discussed.

Allosteric Regulation↗
PubMed1992

Surface potential changes of mitoplasts in the presence of pyridoxal phosphate modified cytochromes c.

1. The addition of native cytochrome c to mitoplasts leads to a decrease of surface potential of the mitoplast membrane. However the surface potential is slightly decreased (approximately 3 mV) when PLP(Lys 86)-cytochrome c and PLP(Lys 79)-cytochrome c were added. 2. The native and PLP-modified cytochromes c do not influence the order parameters S and isotropic constant a when both spin probe I and probe II were used. It is shown that cytochrome c binding to the membrane does not affect the hydrophobic intermembrane area as well as the lipid arrangements of the mitoplast membrane. 3. At low ionic strength there was observed a significant difference in the membrane potential when PLP-cytochromes c were added to the mitoplasts. 4. At high ionic strength the addition of native or PLP-modified cytochromes c does not change the membrane potential.

Cytochrome c Group↗