scholarly journals The effect of a cross-bridging thiol reagent on the catecholamine fluxes of adrenal medulla vesicles

1970 ◽  
Vol 119 (2) ◽  
pp. 265-271 ◽  
Author(s):  
W. Hasselbach ◽  
G. Taugner
Keyword(s):  
Adrenal Medulla ◽  
Initial Phase ◽  
Adenosine Triphosphatase ◽  
Thiol Groups ◽  
Adenosine Triphosphatase Activity ◽  
Bovine Adrenal Medulla ◽  
Thiol Reagent ◽  
Catecholamine Fluxes

The thiol groups of the vesicular protein of bovine adrenal medulla were allowed to react with the bifunctional thiol reagent bis-(N-maleimidomethyl) ether and with the monofunctional thiol reagent N-ethylmaleimide, and the ATP-dependent and -independent catecholamine fluxes of the modified preparations were studied. 1. During the initial phase of the reaction bis-(N-maleimidomethyl) ether blocks twice as many thiol groups as does N-ethylmaleimide at equimolar concentrations. 2. Labelling of the bis-(N-maleimidomethyl) ether–protein compound with [14C]-cysteine shows that 70–80% of the blocked thiol groups are interconnected by the bifunctional thiol reagent. 3. At a low extent of reaction (1.5mol of thiol groups/106g of protein) the catecholamine efflux is diminished. If more than 2mol of thiol groups/106g of protein are blocked, the efflux is enhanced whichever thiol reagent is applied. 4. If 2–4mol of thiol groups/106g of protein are blocked the inhibition of the catecholamine influx increases linearly with the proportion of the thiol groups blocked. 5. ATP protects the catecholamine influx and the adenosine triphosphatase activity against bis-(N-maleimidomethyl) ether poisoning somewhat less effectively than against N-ethylmaleimide poisoning.

scholarly journals The effects of univalent anions on catecholamine fluxes and adenosine triphosphatase activity in storage vesicles from the adrenal medulla

1972 ◽  
Vol 130 (4) ◽  
pp. 969-973 ◽  
Author(s):  
G. Taugner
Keyword(s):  
Adrenal Medulla ◽  
Adenosine Triphosphatase ◽  
Adenosine Triphosphatase Activity ◽  
Bovine Adrenal Medulla ◽  
Storage Vesicles ◽  
Dependent Sequence ◽  
Catecholamine Fluxes

1. Influx and efflux of catecholamine and adenosine triphosphatase activity were studied in storage vesicles of bovine adrenal medulla. 2. In the absence of ATP the influx of catecholamine was slow and was not influenced by various anions, whereas the efflux increased in the sequence of anions given by the lyotrophic series. 3. In the presence of ATP the efflux was enhanced compared with that in the absence of ATP; the anion-dependent sequence, however, in which the efflux increased was the same as in the absence of ATP. 4. The ATP-dependent catecholamine influx and the adenosine triphosphatase activity are correlated. The sequence in which anions affect adenosine triphosphatase activity and catecholamine influx, however, is completely different from the lyotrophic anion series. 5. No correlation was found between adenosine triphosphatase activity and the efflux of catecholamine.

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.

scholarly journals The effect of tropomyosin on the adenosine triphosphatase activity of desensitized actomyosin

1967 ◽  
Vol 105 (3) ◽  
pp. 1235-1243 ◽  
Author(s):  
M. C. Schaub ◽  
S V Perry ◽  
D. J. Hartshorne
Keyword(s):  
Acetic Acid ◽  
Inhibitory Activity ◽  
Adenosine Triphosphatase ◽  
Inhibitory Effect ◽  
Tryptic Digestion ◽  
Prolonged Treatment ◽  
Thiol Groups ◽  
Protein Thiol ◽  
Adenosine Triphosphatase Activity ◽  
Inhibitory Activities

1. Tropomyosin preparations of the Bailey type, and those prepared in the presence of dithiothreitol to prevent oxidation of protein thiol groups, inhibit the Ca2+-activated adenosine triphosphatase (ATPase) of desensitized actomyosin by up to 60%. 2. The inhibitory activity of myofibrillar extracts and tropomyosin survives various agents known to denature proteins but to the action of which tropomyosin is unusually stable, namely heating at 100° and mild tryptic digestion. It is destroyed by prolonged treatment with trypsin. 3. The ethylenedioxybis-(ethyleneamino)tetra-acetic acid (EGTA)-sensitizing factor present in extracts of natural actomyosin and myofibrils could be selectively destroyed, leaving unchanged the inhibitory effect on the Ca2+-activated ATPase. There was no correlation between the EGTA-sensitizing and the Ca2+-activated inhibitory activities of tropomyosin prepared under different conditions. 4. Optimum inhibition was achieved when tropomyosin and the myosin of desensitized actomyosin were present in approximately equimolar proportions. Tropomyosin had no effect on the Ca2+-activated ATPase of myosin measured under similar conditions. 5. Evidence is presented showing that the tropomyosin binds to desensitized actomyosin under the conditions in which the ATPase is inhibited.

Soluble serotonin and catecholamine binding proteins in the bovine adrenal medulla

1993 ◽  
Vol 23 (4) ◽  
pp. 343-350 ◽  
Author(s):  
Jef Pinxteren ◽  
Marlene Jimenez Del Rio ◽  
Carlos Velez Pardo ◽  
Guy Ebinger ◽  
Georges Vauquelin ◽  
...  
Keyword(s):  
Adrenal Medulla ◽  
Binding Proteins ◽  
Bovine Adrenal Medulla
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