scholarly journals REGULATORY MECHANISMS OF CELLULAR RESPIRATION

1948 ◽  
Vol 32 (2) ◽  
pp. 179-190 ◽  
Author(s):  
E. S. Guzman Barron ◽  
Leonard Nelson ◽  
Maria Isabel Ardao
Keyword(s):  
Sodium Arsenite ◽  
Alkylating Agents ◽  
Small Concentration ◽  
Sulfhydryl Groups ◽  
Regulatory Mechanisms ◽  
Cellular Respiration ◽  
Cell Respiration ◽  
Sulfhydryl Reagents ◽  
Protein Moiety ◽  
Sea Urchin Sperm

Oxidizing agents of sulfhydryl groups such as iodosobenzoate, alkylating agents such as iodoacetamide, and mercaptide-forming agents such as cadmium chloride, mercuric chloride, p-chloromercuribenzoate, sodium arsenite, and p-carboxyphenylarsine oxide, added in small concentrations to a suspension of sea urchin sperm produced an increase in respiration. When the concentration was increased there was an inhibition. These effects are explained by postulating the presence in the cells of two kinds of sulfhydryl groups: soluble sulfhydryl groups, which regulate cellular respiration, and fixed sulfhydryl groups, present in the protein moiety of enzymes. Small concentrations of sulfhydryl reagents combine only with the first, thus producing an increase in respiration; when the concentration is increased, the fixed sulfhydryl groups are also attacked and inhibition of respiration is the consequence. Other inhibitors of cell respiration, such as cyanide and urethanes, which do not combine with —SH groups, did not stimulate respiration in small concentration.

scholarly journals Influence of cyclophosphamide on respiration and membrane permeability of plant cells

2014 ◽  
Vol 49 (4) ◽  
pp. 357-361 ◽  
Author(s):  
Maria Podbielkowska ◽  
Alicja Zobel ◽  
Maria Wałęza
Keyword(s):  
Membrane Permeability ◽  
Cell Membranes ◽  
Alkylating Agents ◽  
Plant Cells ◽  
Cellular Respiration ◽  
Cell Respiration ◽  
Experimental Conditions ◽  
Specific Influence

A specific influence of cyclophosphamide, an oncostatic drug of the group of alkylating agents, has been demonstrated on cellular respiration and the permeability of cell membranes. The tested drug under the experimental conditions inhibites cell respiration by about 20-30 per cent as compared with the control. The permeability of the plasmalemma and tonoplast de-creased markedly under the action of cyclophosphamide.

Mg2+-activated ATP hydrolysis and sulfhydryl groups in membranes from human erythrocytes

1970 ◽  
Vol 48 (5) ◽  
pp. 604-612 ◽  
Author(s):  
Frances M. Smith ◽  
Jacob A. Verpoorte
Keyword(s):  
Atp Hydrolysis ◽  
Enzymatic Reaction ◽  
Maximal Activity ◽  
Maximum Activity ◽  
Human Erythrocytes ◽  
Sulfhydryl Groups ◽  
Sulfhydryl Reagents ◽  
Rate Of Reaction ◽  
Rate Profile ◽  
Sigmoid Shape

The ATP-hydrolyzing activity of membranes prepared from human erythrocytes depends on the presence of Mg2+ ions. Maximum activity is observed when the concentrations of Mg2+ and ATP are equal. The pH–rate profile of the enzymatic reaction shows a maximum at pH 7.8. The ATP-hydrolyzing activity has decreased to half the maximal activity at pH 6.3 and 9.8, respectively. The enzyme is inhibited by sulfhydryl reagents like p-chloromercuribenzoate (p-CMB) and N-ethylmaleimide. Membranes that are titrated with NaOH or treated with p-CMB lose up to 30% of their protein content. This loss is reversed when Mg2+ or Mg2+ plus ATP is added. However, neither Mg2+ nor Mg2+ plus ATP detectably alters the rate of reaction between the sulfhydryl groups and specific reagents, nor protects the ATP-hydrolyzing activity from inhibition by p-CMB. The amount of protein which dissociates from the membrane increases with pH. The curve describing this extraction has a sigmoid shape with an inflection point at pH 10.2. Maximum solubilization is obtained at pH 11.2. Thus the results indicate that sulfhydryl groups and also the structure of the membrane are important for the ATP-hydrolyzing activity.

scholarly journals Sulfhydryl reagents induce altered spectrin self-association, skeletal instability, and increased thermal sensitivity of red cells

Blood ◽  
1983 ◽  
Vol 62 (6) ◽  
pp. 1190-1196
Author(s):  
DK Smith ◽  
J Palek
Keyword(s):  
Thermal Stability ◽  
Reduced Glutathione ◽  
Thermal Sensitivity ◽  
Red Cells ◽  
Sulfhydryl Groups ◽  
Sulfhydryl Reagents ◽  
Sulfhydryl Reagent ◽  
Self Association ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Membrane Skeletons

Incubation of erythrocytes with the sulfhydryl reagent N-ethyl- maleimide (NEM) results in altered spectrin self-association and formation of dimers on the membrane. Skeletons isolated from these cells exhibit marked skeletal instability. In addition, NEM treatment induces increased thermal sensitivity of both cells and purified spectrin. These effects were not produced in aerobically incubated glucose-6-phosphate dehydrogenase deficient cells and were therefore presumably not due to depletion of intracellular reduced glutathione. These effects were produced by another permeant sulfhydryl reagent, monobromobimane, but not by its membrane-impermeant derivative. We conclude that spectrin sulfhydryl groups play an important role in spectrin self-association and thermal stability.

Studies on phosphoglyceromutase from chicken breast muscle: number and reactivity of sulfhydryl groups

1976 ◽  
Vol 54 (4) ◽  
pp. 307-320 ◽  
Author(s):  
T. J. Carne ◽  
D. J. McKay ◽  
T. G. Flynn
Keyword(s):  
Enzymatic Activity ◽  
Guanidine Hydrochloride ◽  
Sodium Dodecyl ◽  
Marked Change ◽  
Sulfhydryl Groups ◽  
Breast Muscle ◽  
Performic Acid ◽  
Chicken Breast ◽  
Fluorescence Emission Spectrum ◽  
Sulfhydryl Reagents

Phosphoglyceromutase (PGM) from chicken breast muscle was titrated with p-mercuribenzoate (PMB), 5,5′-dithiobisnitrobenzoate (Nbs2), N-ethylmaleimide (NEM), iodoacetate and iodoacetamide. The effect of all of the sulfhydryl reagents, with the exception of NEM was to cause a loss in enzymatic activity. Addition of KCN following reaction with Nbs2 resulted in the recovery of a small amount of enzymatic activity. In the absence of substrate (3-phosphoglyceric acid) or cofactor (2,3-diphosphoglyceric acid) and in the presence or absence of 6 M guanidine hydrochloride, six sulfhydryl groups per mole of enzyme were titrated with PMB. The total number of sulfhydryl groups determined by amino acid analysis of the performic acid oxidized and carboxymethylated enzyme was also found to be six. Disc gel electrophoresis in sodium dodecyl sulfate indicated that the enzyme is composed of subunits having the same molecular weights which suggests there are three sulfhydryl groups per subunit. Reaction with Nbs2 iodoacetate or iodoacetamide resulted in the modification of only two sulfhydryl groups. In each of the modifications, except that due to iodoacetamide both substrate and cofactor reduced the rate, but not the extent, of the reaction. Substrate was more effective than cofactor in reducing the rate of reaction with sulfhydryl reagents suggesting that a cysteine residue is involved in the binding of substrate. That the involvement is indirect is shown by the lack of protection offered by substrate and cofactor to reaction with iodoacetamide. Inactivation of PGM following titration with sulfhydryl reagents is not likely to be due to a conformational change since none of any significance was indicated by circular dichroism of the treated enzyme. This result was substantiated by the lack of a marked change in the fluorescence emission spectrum of the PMB treated enzyme.

Mechanism for depression of heart sarcolemmal Ca2+ pump by oxygen free radicals

1989 ◽  
Vol 257 (3) ◽  
pp. H804-H811 ◽  
Author(s):  
M. Kaneko ◽  
V. Elimban ◽  
N. S. Dhalla
Keyword(s):  
Free Radicals ◽  
Oxygen Free Radicals ◽  
Sulfhydryl Group ◽  
Sulfhydryl Groups ◽  
Time Dependent ◽  
Dependent Manner ◽  
Protective Effects ◽  
Inhibitory Effects ◽  
Sulfhydryl Reagents ◽  
Dose Dependent

To understand the involvement of changes in sulfhydryl groups in causing depression of the sarcolemmal Ca2+-pump activities, this study was undertaken to examine the effects of oxygen free radicals on rat heart sarcolemmal sulfhydryl groups, Ca2+-stimulated adenosinetriphosphatase (ATPase), and ATP-dependent Ca2+ accumulation. In addition, the effects of sulfhydryl reagents such as dithiothreitol, cysteine, and N-ethylmaleimide on Ca2+-pump activities were investigated. The inhibition of sarcolemmal Ca2+-pump activities by O2-. (xanthine + xanthine oxidase) and H2O2 was decreased by the addition of dithiothreitol or cysteine in a dose-dependent manner. N-ethylmaleimide also showed inhibitory effects on Ca2+-pump activities both in a dose- and time-dependent manner; dithiothreitol and cysteine prevented changes in Ca2+-pump activities because of N-ethylmaleimide. Heart sarcolemmal sulfhydryl groups were depressed by O2-., H2O2, and .OH (H2O2 + Fe2+) both in a dose- and time-dependent manner. Superoxide dismutase, catalase, and D-mannitol showed protective effects on the sulfhydryl group depression by O2-., H2O2, and .OH, respectively. A significant correlation between changes in sarcolemmal Ca2+-stimulated ATPase activity and sarcolemmal sulfhydryl groups was seen. These results indicate that oxygen free radicals may depress the heart sarcolemmal Ca2+-pump activities by modifying the sulfhydryl groups in the sarcolemmal membrane.

scholarly journals Drosophila melanogaster Sperm under Simulated Microgravity and a Hypomagnetic Field: Motility and Cell Respiration

2020 ◽  
Vol 21 (17) ◽  
pp. 5985
Author(s):  
Irina V. Ogneva ◽  
Maria A. Usik ◽  
Maria V. Burtseva ◽  
Nikolay S. Biryukov ◽  
Yuliya S. Zhdankina ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Complex I ◽  
Simulated Microgravity ◽  
Video Recording ◽  
Fruit Fly ◽  
Cellular Respiration ◽  
Cell Respiration ◽  
Hypomagnetic Field ◽  
Essential Phospholipids

The role of the Earth’s gravitational and magnetic fields in the evolution and maintenance of normal processes of various animal species remains unclear. The aim of this work was to determine the effect of simulated microgravity and hypomagnetic conditions for 1, 3, and 6 h on the sperm motility of the fruit fly Drosophila melanogaster. In addition to the usual diet, the groups were administered oral essential phospholipids at a dosage of 500 mg/kg in medium. The speed of the sperm tails was determined by video recording and analysis of the obtained video files, protein content by western blotting, and cell respiration by polarography. The results indicated an increase in the speed of movement of the sperm tails after 6 h in simulated microgravity. The levels of proteins that form the axoneme of the sperm tail did not change, but cellular respiration was altered. A similar effect occurred with the administration of essential phospholipids. These results may be due to a change in the level of phosphorylation of motor proteins. Exposure to hypomagnetic conditions led to a decrease in motility after 6 h against a background of a decrease in the rate of cellular respiration due to complex I of the respiratory chain. This effect was not observed in the flies that received essential phospholipids. However, after 1 h under hypomagnetic conditions, the rate of cellular respiration also increased due to complex I, including that in the sperm of flies receiving essential phospholipids.

scholarly journals REGULATORY MECHANISMS OF CELLULAR RESPIRATION

1948 ◽  
Vol 32 (2) ◽  
pp. 163-178 ◽  
Author(s):  
E. S. Guzman Barron ◽  
John A. Muntz ◽  
Betty Gasvoda
Keyword(s):  
Cell Metabolism ◽  
Dry Weight ◽  
Lactic Dehydrogenase ◽  
Yeast Cells ◽  
Regulatory Mechanisms ◽  
Cellular Respiration ◽  
Degree Of Dissociation ◽  
E Coli ◽  
Oxidation Of Glucose ◽  
Protein Portion

Uranium as UO2(NO3)2 combines reversibly with proteins. The degree of dissociation of this combination depends, among other factors, on the H+ concentration. At pH 7.3 the U-albumin complex was easily dissociated on addition of citrate, while at pH 3.8 it was not. Uranium inhibited reversibly a number of enzyme systems. Uranium enzyme inhibitions could be reversed on addition of certain hydroxypolycarboxylic acids (citric acid, α-hydroxyaspartic acid, malic acid); in no case, however, did phosphate have any effect. In cell-free yeast juice, the fermentation of glucose-hexosediphosphate was inhibited by UO2(NO3)2. Slight reactivation occurred on addition of phosphate. In living yeast cells, the fermentation and oxidation of glucose was inhibited by small amounts of UO2(NO3)2 (7,7 micrograms per mg. dry weight), while the oxidation of acetic acid, ethyl alcohol, malic and citric acids, was not affected at all. U inhibition in living yeast cells at pH 7.3 was completely released on addition of small amounts of phosphate, adenosinetriphosphate, and citrate, while at pH 3.8 U inhibition was not released by phosphate and citrate. At saturation, one yeast cell contained 7.06 x 106 molecules of uranium. Lactic dehydrogenase was not inhibited by U while the oxidation of lactic acid by gonococci was inhibited. Addition of phosphate released this inhibition. The U inhibition of liver succinoxidase was unaffected by phosphate, while the U inhibition of the oxidation of succinate by E. coli was released by phosphate. It has been concluded from these experiments that U inhibition of cell metabolism is due to combination of the metal with the protein portion of the cell membrane. Uranium is presented as an example of surface inhibition.

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