Spectroscopic Evidence of the Participation of the Cytochrome - Cytochrome Oxidase System in the Active Transport of Salts

Nature ◽  
1951 ◽  
Vol 167 (4237) ◽  
pp. 71-71 ◽  
Author(s):  
H. LUNDEGÅRDH
Keyword(s):  
Cytochrome Oxidase ◽  
Active Transport ◽  
Oxidase System ◽  
Spectroscopic Evidence

scholarly journals Studies in The Metabolism of Plant Cells

1950 ◽  
Vol 3 (4) ◽  
pp. 487 ◽  
Author(s):  
DC Weeks ◽  
RN Robertson
Keyword(s):  
Cytochrome Oxidase ◽  
Enzyme Inhibitor ◽  
Plant Cells ◽  
Carrot Root ◽  
Root Cells ◽  
Oxidase System

It has been established with the use of the enzyme inhibitor carbon monoxidethat the cyanide-sensitive salt respiration in carrot root cells is mediatedby the cytochrome-cytochrome oxidase system. The cyanide-stable ground respirationis not mediated by the cytochrome-cytochfome oxidase system.

Reflectance Spectra and Some Respiratory Reactions of Bovine, Equine and Human Thrombocytes

1957 ◽  
Vol 188 (2) ◽  
pp. 415-419 ◽  
Author(s):  
Charles R. Goucher ◽  
W. Kocholaty
Keyword(s):  
Cytochrome C ◽  
Redox Potential ◽  
Cytochrome Oxidase ◽  
Sodium Azide ◽  
Visible Region ◽  
Reflectance Spectra ◽  
Absorption Bands ◽  
Oxidase System ◽  
Chromatic Properties

Reflectance spectra of human, bovine and equine thrombocytes reveal the existence of pigments which absorb in the visible region of the spectrum. The chromatic properties of these pigments change with the redox potential of the cell. These spectra alterations suggest the existence of a cytochrome system, but the position of the absorption bands does not permit their identification with known mammalian cytochromes. However, platelet homogenates contain a cytochrome oxidase which oxidizes mammalian cytochrome c and which is inhibited by sodium azide. Platelet extracts also contain a DPNH oxidase system which is inhibited by sodium azide.

scholarly journals INFLUENCE OF SULFHYDRYL REAGENTS ON THE CYTOCHROME c-CYTOCHROME OXIDASE SYSTEM

1950 ◽  
Vol 185 (2) ◽  
pp. 469-477
Author(s):  
Cornelius W. Kreke ◽  
Sister M. Albertus Schaefer ◽  
Sister M. Angelice Seibert ◽  
Elton S. Cook
Keyword(s):  
Cytochrome C ◽  
Cytochrome Oxidase ◽  
Sulfhydryl Reagents ◽  
Oxidase System

Mise en évidence d'activités enzymatiques au niveau de l'haustorium d'une phanérogame parasite : Striga hermonthica (Scrophulariaceae)

1979 ◽  
Vol 57 (22) ◽  
pp. 2564-2571 ◽  
Author(s):  
Amadou Tidiane Ba ◽  
Guy Kahlem
Keyword(s):  
Acid Phosphatase ◽  
Succinate Dehydrogenase ◽  
Cytochrome Oxidase ◽  
Active Transport ◽  
Enzymatic Activities ◽  
Striga Hermonthica ◽  
Radial System ◽  
Host Penetration ◽  
Penetration Mechanism

Acid phosphatase, ATPase, peroxidase, succinate dehydrogenase, and cytochrome oxidase activities have been demonstrated in the haustorium of Striga hermonthica, a parasitic phanerogam on millet (Pennisetum typhoideum var. Sonna 3). Their localization has been specified and their possible role discussed. These enzymatic activities seem to be related to the host penetration mechanism and also with the process of active transport of solutes between host and parasite. A tracheid radial system has also been discovered in the mature haustorium.

Effect of inhibitors on the activity of soluble succinic dehydrogenase and on the reconstitution of the succinic dehydrogenase-cytochrome system from its components

1960 ◽  
Vol 152 (947) ◽  
pp. 163-187 ◽  
Keyword(s):  
Methylene Blue ◽  
Cytochrome Oxidase ◽  
Molecular Oxygen ◽  
Heart Muscle ◽  
Succinic Dehydrogenase ◽  
Reversible Reaction ◽  
Muscle Preparation ◽  
Oxidase System ◽  
Sites Of Action ◽  
Phenazine Methosulphate

The succinic dehydrogenase-cytochrome system, which catalyzes the oxidation of suecinate to fumarate by molecular oxygen, was successfully reconstituted from soluble succinic dehydrogenase, soluble cytochrome c and a particulate heart-muscle preparation which is deprived of these components but contains cytochromes a 3 , a , c 1 and b and has a strong cytochrome oxidase activity. Although succinic dehydrogenase isolated in a soluble form by Singer and by Wang with their co-workers was identified by them as a flavoprotein compound containing one modified flavin adenine dinucleotide and 2 or 4 iron atoms, neither the function of the iron nor the structure and function of the flavin group have so far been satisfactorily elucidated. Soluble succinic dehydrogenase, unlike its endogenous form, is very unstable and catalyzes the oxidation of succinate by phenazine methosulphate or ferricyanide but not by cytochrome c or methylene blue. However, when soluble enzyme is re-incorporated within the particles of the heart-muscle preparation deprived of this enzyme, it becomes an integral part of the respiratory chain and re-acquires all the properties of its endogenous form, that is insolubility, stability and reactivity towards the cytochrome system and methylene blue. The succinic dehydrogenase-cytochrome system thus reconstituted, on addition of cytochrome c , actively catalyzes the oxidation of succinate by molecular oxygen. It shows normal oxidation and reduction of its cytochrome components and is susceptible to all inhibitors in the same way as is the succinic oxidase system of an untreated heart-muscle preparation. The comparative study of a soluble succinic dehydrogenase and a particulate succinic oxidase system revealed: (i) that pyrophosphate, like malonate and oxalacetate, acts as a competitive inhibitor of the succinic dehydrogenase itself; (ii) that narcotics have two sites of action: like antimycin they break the link between cytochromes b and c 1 and, unlike antimycin, they also inhibit, but to a lesser degree, the activity of succinic dehydrogenase; and (iii) that cyanide can react with three components of this system in three different ways: a rapid and perfectly reversible reaction with cytochrome oxidase, a slow and still reversible reaction with oxidized soluble cytochrome c and a slow, irreversible reaction with the succinic dehydrogenase itself. It was previously shown (Tsou 1951) that the incubation of heart-muscle preparation with cyanide irreversibly inhibited the oxidation of succinate via the cytochrome system or methylene blue. Although cyanide treatment of soluble succinic dehydrogenase does not inhibit its catalytic activity in the oxidation of succinate by phenazine methosulphate, it prevents the dehydrogenase from anchoring itself within the particles of the heart-muscle preparation deprived of this enzyme, and so the reconstitution of the particulate succinic oxidase system does not take place. As the cyanide effect of Tsou is slow, irreversible, sensitive to temperature, complete and can be prevented by reducing substances, such as succinate acting as a hydrogen donor, or sodium dithionite, but not by malonate or pyrophosphate, we postulated: (i) that this effect is due to an irreversible reduction by cyanide of a disulphide group of succinic dehydrogenase to one thiol and one thiocyanate group, and (ii) th at this disulphide group originates by a reversible oxidation of a dithiol group which is present in addition to, and differs in several respects from the dithiol group of Hopkins.

scholarly journals CHEMICAL PACEMAKERS

1939 ◽  
Vol 23 (1) ◽  
pp. 81-99 ◽  
Author(s):  
Zareh Hadidian ◽  
Hudson Hoagland
Keyword(s):  
Cytochrome Oxidase ◽  
Enzyme System ◽  
Basic Theory ◽  
Energy Of Activation ◽  
Brain Iron ◽  
Brain Wave ◽  
Oxidase System ◽  
Brain Infection ◽  
Subsequent Addition ◽  
Physiological Systems

1. Iron spicules found in the brains of general paretic patients are formed from endogenous brain iron normally present in another form. This supports our earlier view that the µ value of 16,000 obtained in advanced paretics for alpha brain wave frequencies as a measure of cortical respiration comes about from the slowing of an iron catalyzed link in cortical respiration such as would result from the reduction of available cytochrome and its oxidase, thus making this step a chemical pacemaker. 2. To test the basic theory of chemical pacemakers, a study was made of the succinate-fumarate enzyme system containing succino-dehydrogenase and cytochrome-cytochrome oxidase acting sequentially. 3. The µ value for the unpoisoned system is 11,200 ± 200 calories. 4. According to theory, the addition of a critical amount of cyanide known to be a specific poison of the cytochrome-cytochrome oxidase system (and not of the dehydrogenase) should shift the µ cleanly to 16,000 calories, and it does. 5. According to theory, selenite, a specific poison for the dehydrogenase, should stop all respiration without shifting the µ. This also is found to be the case. 6. The theory also predicts that if the µ is shifted from 11,000 ± to 16,000 ± by cyanide, the subsequent addition of a critical amount of selenite should shift the µ back again to 11,000 ± calories, and this is found to occur. 7. It is concluded that approximately 11,000 calories is the energy of activation of the succino-dehydrogenase-catalyzed step and 16,000 calories is that for the cytochrome-cytochrome oxidase-catalyzed step. These two values are encountered more frequently than any others in physiological systems. It is to be recalled that a shift of µ for alpha brain wave frequencies from 11,000 to 16,000 calories occurs in the course of advancing syphilitic brain infection and is accompanied by a change in form of brain iron.

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