A Hypothesis linking the Succinic Dehydrogenase System to an Intermediate of Oxidative Phosphorylation

Nature ◽  
1963 ◽  
Vol 199 (4891) ◽  
pp. 377-378 ◽  
Author(s):  
OSCAR GAWRON
Keyword(s):  
Oxidative Phosphorylation ◽  
Succinic Dehydrogenase ◽  
Dehydrogenase System

scholarly journals IN VITRO EFFECTS OF FLUORIDE ON TRICARBOXYLIC ACID CYCLE DEHYDROGENASES AND OXIDATIVE PHOSPHORYLATION: PART I

1967 ◽  
Vol 15 (4) ◽  
pp. 195-201 ◽  
Author(s):  
C. JAMES LOVELACE ◽  
GENE W. MILLER
Keyword(s):  
Oxidative Phosphorylation ◽  
Competitive Inhibition ◽  
Tricarboxylic Acid Cycle ◽  
Succinic Dehydrogenase ◽  
Tricarboxylic Acid ◽  
Initial Increase ◽  
Acid Cycle ◽  
Oxidase System ◽  
Vitro Effect

Studies were conducted on the in vitro effect of fluoride on the succinic oxidase system utilizing mitochondria obtained from cauliflower. Preincubation of mitochondria with fluoride did not increase inhibition of succinic oxidase. Various other tricarboxylic acid cycle substrates were used to determine their sensitivity to fluoride; only succinate oxidation was affected. A series of succinate concentrations in the presence and in the absence of fluoride showed increased activity of succinic dehydrogenase, which indicated competitive inhibition. Various concentrations of phosphate in the absence of fluoride showed that phosphate had only slight effects on the succinic 2,6-dichlorophenolindophenol reductase component of the succinic oxidase system. In the absence of phosphate, various concentrations of fluoride showed an initial increase in activity followed by a decrease in activity of succinic 2,6-dichlorophenolindophenol reductase. In the presence of phosphate, fluoride caused marked inhibition of succinic 2,6-dichlorophenolindophenol reductase. It is believed that this inhibition results from an enzyme-fluorophosphate complex which has a lower dissociation constant than that of the enzyme-substrate complex. An oxidative phosphorylation study indicated that both respiration and phosphorylation were inhibited.

scholarly journals A Histochemical Method for the Demonstration of Diphosphopyridine Nucleotide Diaphorase

1958 ◽  
Vol 4 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Marvin M. Nachlas ◽  
Donald G. Walker ◽  
Arnold M. Seligman
Keyword(s):  
Gastric Mucosa ◽  
Rat Kidney ◽  
Succinic Dehydrogenase ◽  
Lactic Dehydrogenase ◽  
Histochemical Demonstration ◽  
Cytochemical Localization ◽  
Dehydrogenase System ◽  
Special Distribution ◽  
Almost All ◽  
Mucous Lining

The present investigation concerning the histochemical demonstration of DPN diaphorase follows the development of a new reagent, Nitro-BT, which has already been used successfully for the cytochemical localization of the succinic dehydrogenase system. The most consistently favorable results were obtained with the lactate-lactic dehydrogenase system buffered at pH 7.4. Using sections of rat kidney and stomach, it was found that the intensity of stain was optimal after 15 minutes incubation at 37°C., conducted aerobically. By appropriate variations in the substrate mixture it was possible to selectively demonstrate the histochemical distribution of certain DPN-linked dehydrogenases in addition to DPN diaphorase. This was made possible by the special distribution of some of these dehydrogenases which distinguished them from one another. Of the dehydrogenases studied the distribution pattern of ß-hydroxybutyric dehydrogenase was the most singular. In the gastric mucosa ß-hydroxybutyric dehydrogenase was restricted to the cells of the mucous lining epithelium and the gland necks; and in the kidney the enzyme was limited to the cells of the proximal convoluted tubule and thick limbs of Henle's loop. In contrast, lactic dehydrogenase like DPN diaphorase was demonstrable in almost all cytologic elements of both the stomach and the kidney.

scholarly journals ELECTRON MICROSCOPIC AND HISTOCHEMICAL OBSERVATIONS OF MUSCLE DEGENERATION AFTER TOURNIQUET

1956 ◽  
Vol 2 (6) ◽  
pp. 755-764 ◽  
Author(s):  
Dan H. Moore ◽  
Helmut Ruska ◽  
Wilfred M. Copenhaver
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Model ◽  
Fiber Type ◽  
Succinic Dehydrogenase ◽  
Muscle Degeneration ◽  
Electron Microscopic ◽  
The Status ◽  
Dehydrogenase System

As an experimental model for the different forms of muscle degeneration, injury caused by 2 hours' ischemia has been studied from 20 minutes to 16 hours after release of the tourniquet. Discoid degeneration developed in stretched fibers by dissolution of the I bands (Z substances and actin). The discs represented the Q bands (A-H-A). In fibers which passively maintained contraction lengths during degeneration, the Z substances were dissolved, but the continuity of the fibrils was preserved, since the filaments are continuous over all sarcomeres under these conditions. Mitochondria and the tubules of the endoplasmic reticulum swelled, ruptured, and disintegrated. Granular degeneration developed in fibers where mitochondria were abundant. Unstretched degenerating fibers with few mitochondria gave a homogeneous or hyaline appearance. The different forms of degeneration therefore were dependent on the status of stretch and the fiber type. The extent of degeneration was not a function of time after ischemia, there being both nearly normal and severely damaged fibers at 20 minutes and 16 hours after the release of tourniquets. When degeneration occurred, however, the basic alterations were the same in all fibers; there was mitochondrial and reticular swelling, dissolution of the Z substances, and finally disintegration of the contractile material. Some damage developed in the sarcolemmas and capillaries. The mitochondrial disintegration was not linked with inactivation of the succinic dehydrogenase system.

ENZYME INHIBITION BY DERIVATIVES OF PHENOTHIAZINE: III. CATALASE, CYTOCHROME OXIDASE, AND DEHYDROGENASES

1942 ◽  
Vol 20b (12) ◽  
pp. 284-290 ◽  
Author(s):  
H. Bruce Collier ◽  
Della E. Allen
Keyword(s):  
Cytochrome Oxidase ◽  
Succinic Dehydrogenase ◽  
Lactic Dehydrogenase ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Leuco Form ◽  
Dehydrogenase System ◽  
Living Organisms ◽  
Relationship Of ◽  
Derivatives Of

The inhibition of liver catalase and of cytochrome oxidase by leucophenothiazone has been confirmed by manometric methods. Phenothiazine sulphoxide is a powerful catalase inhibitor, its activity being much greater at pH 5.3 than at neutrality.The succinoxidase activity of beef heart is inhibited by phenothiazone and by thionol. Phenothiazone in its oxidized form acts upon the succinic dehydrogenase, while the leuco form inhibits the cytochrome oxidase.Phenothiazone is reduced by the yeast lactic dehydrogenase system, and the enzyme activity is markedly decreased. Urease is also partially inhibited, whereas the effect of phenothiazone upon d-amino-acid oxidase is almost negligible.The possible relationship of these findings to the action of phenothiazine upon living organisms is discussed.

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