Kinetic studies on soluble and membrane-bound dopamineβ-hydroxylase isolated from storage vesicles of heart and adrenal medulla of different species

1976 ◽  
Vol 32 (8) ◽  
pp. 984-986 ◽  
Author(s):  
O. -E. Brodde ◽  
F. Arens ◽  
K. Huvermann ◽  
H. J. Schümann
Keyword(s):  
Adrenal Medulla ◽  
Kinetic Studies ◽  
Storage Vesicles ◽  
Membrane Bound

Allosteric interactions between the membrane-bound acetylcholine receptor and chemical mediators. Kinetic studies

Biochemistry ◽  
1977 ◽  
Vol 16 (4) ◽  
pp. 684-692 ◽  
Author(s):  
James E. Bulger ◽  
Juian-Juian L. Fu ◽  
Ellen F. Hindy ◽  
Richard L. Silberstein ◽  
George P. Hess
Keyword(s):  
Acetylcholine Receptor ◽  
Kinetic Studies ◽  
Allosteric Interactions ◽  
Membrane Bound ◽  
Chemical Mediators

scholarly journals The effect of salts on catecholamine fluxes and adenosine triphosphatase activity in storage vesicles from the adrenal medulla

1971 ◽  
Vol 123 (2) ◽  
pp. 219-225 ◽  
Author(s):  
G. Taugner
Keyword(s):  
Potassium Chloride ◽  
Adrenal Medulla ◽  
Sodium Nitrate ◽  
Adenosine Triphosphatase ◽  
Sodium Succinate ◽  
Adenosine Triphosphatase Activity ◽  
Storage Vesicles ◽  
Sucrose Medium ◽  
Catecholamine Fluxes ◽  
Net Release

1. Influx and efflux of catecholamine and adenosine triphosphatase activity in storage vesicles from the adrenal medulla were studied with dl-[14C]adrenaline in different media. 2. The lowest values for flux and adenosine triphosphatase activity were observed in sucrose media in which an ATP-dependent influx of catecholamine compensated for an efflux of the same magnitude. Efflux in the presence or absence of ATP was similar. 3. In media containing sodium succinate or glutarate adenosine triphosphatase activity was higher and the ATP-dependent influx of catecholamine was about twice that observed in iso-osmotic sucrose medium. In the presence of ATP influx and efflux of catecholamine were balanced; in its absence there was a net release of catecholamine, since efflux was more than twice the influx. Efflux in the presence or absence of ATP was similar. 4. In media containing sodium or potassium chloride and in the presence of ATP influx and adenosine triphosphatase activity were further enhanced, but in the absence of ATP there was no further increase in influx, since catecholamine was released with or without ATP at the same rate. Efflux was therefore twice as high in the presence of ATP as in its absence. 5. Sodium nitrate suppressed the ATP-dependent influx nearly completely, but caused a greatly enhanced efflux, which was twice as high in the presence of ATP as in its absence. 6. The extinction of vesicular suspensions remained unchanged in the presence of ATP under conditions where the catecholamine efflux was balanced by the influx. Under conditions where the efflux was not compensated by influx, the extinction of the suspensions decreased in the presence of ATP more than in its absence.

Chromogranin A, dopamine β-hydroxylase and secretion from the adrenal medulla

1971 ◽  
Vol 261 (839) ◽  
pp. 279-289 ◽  
Keyword(s):  
Adrenal Medulla ◽  
Synaptic Vesicles ◽  
Adenine Nucleotides ◽  
Sympathetic Nerves ◽  
Neural Stimulation ◽  
Secretory Process ◽  
Vesicle Membrane ◽  
The Past ◽  
Storage Vesicles ◽  
Experimental Approaches

Studies of the biosynthesis, storage and secretion of catecholamines by the adrenal medulla have served as models for similar studies of the adrenergic neuron. For example, the synthesis of noradrenaline and the intracellular distribution of the biosynthetic enzymes was first described in the adrenal medulla and subsequently shown to be the same in sympathetic nerves (Blaschko 1939; Kirshner 1957, 1959; Levin, Levenberg & Kaufman i960; Potter & Axelrod 1963; Nagatsu, Levitt & Udenfriend 1964; Stjarne & Lishajko 1966; Oka et al. 1967; Musacchio 1968; Laduron & Belpaire 1968). The storage vesicles of the adrenal medulla have counterparts in the synaptic vesicles (Blaschko & Welch 1953; Hillarp, Lagerstedt & Nilson 1953; von Euler & Hillarp 1956; Schumann 1958) and the incorporation of catecholamines into the storage vesicles, and the storage complex itself, seems to be similar in both tissues, (Kirshner 1962; Carlsson, Hillarp & Waldeck 1963; von Euler & Lishajko 1963; von Euler, Lishajko & Stjarne 1963; Stjarne 1964). Recently it has been demonstrated that proteins specifically localized in the storage vesicles of the adrenal medulla are also present in the storage vesicles of sympathetic nerve endings (Hopwood 1967, 1968; Geffen, Livett & Rush 1969; Banks, Helle & Major 1969; de Potter, de Schaepdryver, Moerman & Smith 1969). There are obvious differences between the two types of vesicles (Stjarne 1964; Potter 1967), but the similarities are such as to suggest that the vesicles from both tissues serve the same physiological functions—to synthesize and store adrenaline or noradrenaline and to release these compounds in response to neural stimulation. Secretion from the adrenal medulla appears to be a good model for release of neurotransmitters at synapses in the sense that it provides and suggests experimental approaches to the problem (Geffen et al. 1969; de Potter et al. 1969). In general, the secretion of substances which are synthesized in cells and stored in subcellular organelles have many features in common (Douglas 1968; Stormorken 1969) and release of neurotransmitters at synapses may be another example of this generalized biological process. During the past few years, evidence has been presented from several laboratories that secretion from the adrenal medulla occurs by exocytosis. The simultaneous release of catecholamines, adenine nucleotides, chromogranins and soluble dopamine β-hydroxylase contained within the storage vesicles and the retention of dopamine-β- hydroxylase firmly bound to the vesicle membrane have provided critical information on this secretory process.

Kinetic studies on cytosol and membrane-bound protein kinases of human erythrocytes

1979 ◽  
Vol 10 (2) ◽  
pp. 171-175 ◽  
Author(s):  
E. Michielin ◽  
G. Clari ◽  
V. Moret
Keyword(s):  
Protein Kinases ◽  
Kinetic Studies ◽  
Human Erythrocytes ◽  
Membrane Bound

The membrane of atecholamine storage vesicles of adrenal medulla

1972 ◽  
Vol 274 (3) ◽  
pp. 299-314 ◽  
Author(s):  
G. Taugner
Keyword(s):  
Adrenal Medulla ◽  
Storage Vesicles

scholarly journals Cryo-EM structure and kinetics reveal electron transfer by 2D diffusion of cytochrome c in the yeast III-IV respiratory supercomplex

2020 ◽  
Author(s):  
Agnes Moe ◽  
Justin Di Trani ◽  
John L. Rubinstein ◽  
Peter Brzezinski
Keyword(s):  
Electron Transfer ◽  
Respiratory Chain ◽  
Supramolecular Assembly ◽  
Kinetic Studies ◽  
Water Soluble ◽  
Complex Iii ◽  
Surface Patch ◽  
Cellular Respiration ◽  
Oxidoreductase Activity ◽  
Membrane Bound

AbstractEnergy conversion in aerobic organisms involves an electron current from low-potential donors, such as NADH and succinate, to dioxygen through the membrane-bound respiratory chain. Electron transfer is coupled to transmembrane proton transport that maintains the electrochemical proton gradient used to produce ATP and drive other cellular processes. Electrons are transferred between respiratory complexes III and IV (CIII and CIV) by water-soluble cyt. c. In S. cerevisiae and some other organisms, these complexes assemble into larger CIII2CIV1/2 supercomplexes, the functional significance of which has remained enigmatic. In this work, we measured the kinetics of the S. cerevisiae supercomplex’s cyt.c-mediated QH2:O2 oxidoreductase activity under various conditions. The data indicate that the electronic link between CIII and CIV is confined to the surface of the supercomplex. Cryo-EM structures of the supercomplex with cyt. c reveal distinct states where the positively-charged cyt. c is bound either to CIII or CIV, or resides at intermediate positions. Collectively, the structural and kinetic data indicate that cyt. c travels along a negatively-charged surface patch of the supercomplex. Thus, rather than enhancing electron-transfer rates by decreasing the distance cyt. c must diffuse in 3D, formation of the CIII2CIV1/2 supercomplex facilitates electron transfer by 2D diffusion of cyt. c. This mechanism enables the CIII2CIV1/2 supercomplex to increase QH2:O2 oxidoreductase activity and suggests a possible regulatory role for supercomplex formation in the respiratory chain.Significance StatementIn the last steps of food oxidation in living organisms, electrons are transferred to oxygen through the membrane-bound respiratory chain. This electron transfer is mediated by mobile carriers such as membrane-bound quinone and water-soluble cyt. c. The latter transfers electrons from respiratory complex III to IV. In yeast these complexes assemble into III2IV1/2 supercomplexes, but their role has remained enigmatic. This study establishes a functional role for this supramolecular assembly in the mitochondrial membrane. We used cryo-EM and kinetic studies to show that cyt. c shuttles electrons by sliding along the surface of III2IV1/2 (2D diffusion). The structural arrangement into III2IV1/2 supercomplexes suggests a mechanism to regulate cellular respiration.

The membrane of the catecholamine storage vesicles of the adrenal medulla

Histochemie ◽  
1972 ◽  
Vol 33 (3) ◽  
pp. 255-272 ◽  
Author(s):  
B. Agostini ◽  
G. Taugner
Keyword(s):  
Adrenal Medulla ◽  
Storage Vesicles ◽  
Catecholamine Storage

scholarly journals Energization of the transport systems for arabinose and comparison with galactose transport in Escherichia coli

1981 ◽  
Vol 200 (3) ◽  
pp. 611-627 ◽  
Author(s):  
K R Daruwalla ◽  
A T Paxton ◽  
P J Henderson
Keyword(s):  
Escherichia Coli ◽  
Transport System ◽  
Membrane Vesicles ◽  
Kinetic Studies ◽  
Transport Systems ◽  
Protonmotive Force ◽  
Alkaline Ph ◽  
Ph Change ◽  
Intact Cells ◽  
Membrane Bound

1. Strains of Escherichia coli were obtained containing either the AraE or the AraF transport system for arabinose. AraE+,AraF- strains effected energized accumulation and displayed an arabinose-evoked alkaline pH change indicative of arabinose-H+ symport. In contrast, AraE-,AraF+ strains accumulated arabinose but did not display H+ symport. 2. The ability of different sugars and their derivatives to elicit sugar-H+ symport in AraE+ strains was examined. Only L-arabinose and D-fucose were good substrates, and arabinose was the only inducer. 3. Membrane vesicles prepared from an AraE+,AraF+ strain accumulated the sugar, energized most efficiently by the respiratory substrates ascorbate + phenazine methosulphate. Addition of arabinose or fucose to an anaerobic suspension of membrane vesicles caused an alkaline pH change indicative or sugar-H+ symport on the membrane-bound transport system. 4. Kinetic studies and the effects of arsenate and uncoupling agents in intact cells and membrane vesicles gave further evidence that AraE is a low-affinity membrane-bound sugar-H+ symport system and that AraF is a binding-protein-dependent high-affinity system that does not require a transmembrane protonmotive force for energization. 5. The interpretation of these results is that arabinose transport into E. coli is energized by an electrochemical gradient of protons (AraE system) or by phosphate bond energy (AraF system). 6. In batch cultures the rates of growth and carbon cell yields on arabinose were lower in AraE-,AraF+ strains than in AraE+,AraF- or AraE+,AraF+ strains. The AraF system was more susceptible to catabolite repression than was the AraE system. 7. The properties of the two transport systems for arabinose are compared with those of the genetically and biochemically distinct transport systems for galactose, GalP and MglP. It appears that AraE is analogous to GalP, and AraF to MglP.

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