PubMed Health⌕ Search

Biomedical subjects

M Antalík

Publications and source records attributed to M Antalík.

28 records · Page 2Linked to original sources
PubMed1993

Interaction of carbonyl cyanide 3-chlorophenylhydrazone with cytochrome c oxidase.

Cytochrome c oxidase binds protonophore carbonyl cyanide 3-chlorophenylhydrazone (CCCP) with high affinity. There are 1.46 high-affinity binding sites per cytochrome c oxidase for CCCP with dissociation constant 2.7 x 10(-7) mol/l. The bond between the CCCP and cytochrome c oxidase accomplishes through the group on cytochrome c oxidase with pKa 6.64 and is based on the electrostatic interaction. Interaction of CCCP with low-affinity binding sites of cytochrome c oxidase induces the shift of the anion CCCP spectrum to UV-region. The similar effect is characteristic for CCCP interaction with protons. Lipophilic non-dissociated derivative NCH3CCP is not binding to cytochrome c oxidase.

Binding Sites↗
PubMed1993

Study of the complex formation between amine local anesthetics and uncouplers of oxidative phosphorylation carbonyl cyanide phenylhydrazones.

Spectroscopic evidence is presented which indicates that the anionic uncoupler carbonyl cyanide-4-nitro-2-chloro-phenylhydrazone and the amine local anesthetics form a complex in aqueous solution. The complex formation studies were carried out for several pharmacologically important tertiary amines and some primary amines. Their relative potencies to form a complex with uncoupler have followed the order: procaine < trimecaine < tetracaine < dibucaine < dodecylamine < dicyclohexylamine < hexadecylamine. As to the more lipophilic nature of the complex the emphasized penetration into octanol and reinforced retention into mitochondria was observed. The higher ability of the complex to colapse the mitochondrial membrane potential confirms this fact. The effective concentration of amine local anesthetics to form a complex was correlated with their physicochemical properties namely lipophilicity and acidobasicity. The highest effectivities for complex formation is shown by the most lipophilic and the most ionized molecules of amines. Present results point to the importance of considering the role of amine anesthetic-uncoupler complex in interpreting physiological or ion transport data in which these substances have been used together.

Amines↗
PubMed1992

Spectrophotometric detection of the interaction between cytochrome c and heparin.

Heparin inhibits transport of electrons from reduced cytochrome c to cytochrome c oxidase. The effect is due to the interaction of heparin with cytochrome c. It has been observed that binding of heparin to the reduced or oxidized cytochrome c changes the spectrum of cytochrome c at the Soret region. Affinity chromatography of heparin in cytochrome c immobilized to thiol-Sepharose shows that commercial heparin is eluted in the low-affinity and high-affinity fractions. Both participate in the interaction with cytochrome c. Polylysine induces decay of the cytochrome c-heparin complex.

Chromatography, Affinity↗
PubMed1992

Effect of cytochrome C oxidase and polyanions on the alkaline transition of ferricytochrome C.

Application of heparin, polyadenylate, polyglutamate and polygalacturonate resulted in changes in the electron absorption spectrum of cytochrome c that resembled those after cytochrome c oxidase application at neutral pH. The formed complexes of cytochrome c with polyanions retain the bond of Met-80 with heme iron. Cytochrome c oxidase and the polyanions increased the apparent pKa of alkaline transition of cytochrome c by an order of magnitude.

Animals↗
PubMed1992

Absorption and Raman spectroscopy study of cyt c-thiol complexes in acidic solutions.

Absorption UV-VIS and pre-resonance Raman spectra of acidic cyt c solutions with a series of thiols added (thiophenol, n-propanethiol, isopropanethiol, L-cysteine, dithiothreitol, 2-mercaptoethanol, N-acetyl-L-cysteine, p-acetamidothiophenol, 2-mercaptoethanamine, thioglycolic acid and mercaptopropionic acid), are presented. Interactions of cyt c molecule with the thiols were studied with the aim to identify binding of the thiols with the cyt c heme as its iron axial ligands. Absorption and Raman spectra showed some correlation between maxima of 700 nm region absorption band (typical for Fe-S axial bond in cyt c heme) and also wave numbers of spin state marker and axial ligand sensitive Raman bands on one, and pKa constant values of appropriate thiols on the other hand. These results imply thiol replacement of Met-80 from axial bond with heme iron and suggest that the force of Fe-L-cysteine axial bond is very close to the native axial bond (Fe-Met) for cyt c in neutral solution.

Cytochrome c Group↗
PubMed1991

Effects of N-tricyanovinylamines on oxidative phosphorylation and level of SH-groups in rat liver mitochondria.

The effects of N-substituted tricyanovinylamines on oxidative phosphorylation as well as on glutathione and total SH group concentrations in rat liver mitochondria was studied. The N-TCVA derivatives studied (N-cyclohexyl; N-isobutyl; N-benzyl; N-phenyl; N-4-Br-phenyl; N-3-nitrophenyl) had an uncoupling effection on the oxidative phosphorylation. They stimulated the respiration of mitochondria and influenced their membrane potential. In their property as SH agents, the N-TCVA derivatives reduced the level of TSH groups of the mitochondria present in concentrations of 2 mumol/mg protein. The activity of succinate dehydrogenase was decreased by N-TCVA by 13%. N-TCVA derivatives changed the redox state of glutathione in mitochondria. This effect was observed at the concentration 0.3 mumol/mg protein. The results obtained in the present study support the view that the glutathione status is more sensitive than the total level of SH groups to incubation of mitochondria with SH agents such as N-TCVA derivatives.

Amines↗
PubMed1988

Uncoupling effect of protonophoric and nonprotonophoric analogs of carbonyl cyanide phenylhydrazone on mitochondrial oxidative phosphorylation.

Analogs of carbonyl cyanide phenylhydrazone providing no reaction with nucleophilic groups and lacking acidobasic properties, respectively, were synthesized for study of mechanism of uncoupling effect on oxidative phosphorylation. Their retention, influence on proton transport, abilities to SH--groups modify and to stimulate respiration in rat liver mitochondria, together with their physico-chemical properties, namely lipophilicity, acidobasicity and reactivity were characterized. The substitution of acidic hydrogen of the imino group resulted in the loss of both acidobasicity and uncoupling effect on oxidative phosphorylation. A decreased reactivity resulted from the substitutions of nitrile groups with the uncoupling activity remaining preserved.

Animals↗
PubMed1987

Metabolic and physiological consequences of the effect of phenylhydrazonopropanedinitriles on Candida albicans.

Phenylhydrazonopropanedinitrile, a model uncoupler of oxidative phosphorylation, was used in studies of metabolic and physiological consequences of uncoupling at the cellular level in Candida albicans. Concentrations stimulating respiration induce a faster glucose consumption at a practically unchanged respiratory coefficient. The extracellular production of acids is also without significant changes. When applying higher concentrations of the uncoupler respiration was inhibited, similarly to glucose consumption and acid production. This fact is due to nonspecific interactions of the alkylation type with mercapto groups of functional proteins. Phenylhydrazonopropanedinitrile influences energy-generating processes resulting in slowing down or interruption of biosynthetic processes and occasionally even growth of Candida albicans.

Candida albicans↗
PubMed1986

Quantitative structure-activity relationship of carbonylcyanide phenylhydrazones as uncouplers of mitochondrial oxidative phosphorylation.

The dependence of the uncoupling activity in the series of 16 carbonylcyanide phenylhydrazones on their physico-chemical properties (partition coefficient, dissociation constant and rate constant for reaction with thiols) is investigated using two physiologically based models, one for protonophoric mechanism of uncoupling and the other assuming the covalent modification of a membrane constituent to be the key step in this process. As indicated by uptake experiments, at the given conditions a lipophilic-hydrophilic equilibrium is attained without any loss of the compounds via chemical reactions. Using this fact to reduce the number of adjustable parameters, a better fit to the data on stimulation of respiration is obtained with the former (protonophoric) model.

Animals↗