scholarly journals Identification of a sialoglycopeptide released by self-digestion from human erythrocyte membranes

1976 ◽  
Vol 158 (2) ◽  
pp. 497-500 ◽  
Author(s):  
A Brovelli ◽  
G Pallavicini ◽  
F Sinigaglia ◽  
C L Balduini ◽  
C Balduini
Keyword(s):  
Amino Acids ◽  
Chemical Composition ◽  
Human Erythrocyte ◽  
Molecular Size ◽  
Erythrocyte Membranes ◽  
Erythrocyte Ghosts ◽  
Human Erythrocyte Membranes

Membranes from human O Rhesus-positive erythrocyte ‘ghosts’ were tested in vitro for their ability to digest their own glycoproteins. ‘Ghost’ membranes incubated in Tris/HCl buffer, pH 7.4, release a sialoglycopeptide, which contains glucosamine, galactosamine, galactose and mainly polar amino acids. Chemical composition, molecular size and aggregation properties suggest that this glycopeptide may be a fragment of glycophorin.

Thyroid hormone stimulates release of calmodulin-enhancing activity from human erythrocyte membranes in vitro

1993 ◽  
Vol 84 (2) ◽  
pp. 217-223 ◽  
Author(s):  
William D. Lawrence ◽  
Mark R. Deziel ◽  
Paul J. Davis ◽  
Marion Schoenl ◽  
Faith B. Davis ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Soluble Factor ◽  
Heat Stable ◽  
Enhancing Factor ◽  
Human Erythrocyte Membranes ◽  
Subsequent Addition ◽  
Stable Control

1. Thyroid hormone (L-thyroxine, 10−10mol/l) incubated in vitro with human erythrocyte membranes induced the release of a soluble calmodulin-like material, the 3′:5′-cyclic nucleotide phosphodiesterase-stimulating activity of which was at least six-fold greater than its concentration measured by a specific calmodulin radioimmunoassay. 2. The material had the characteristics of calmodulin in that it stimulated both phosphodiesterase and erythrocyte Ca2+-ATPase activities, cross-reacted with and was neutralized by anti-calmodulin antibody, was adsorbed by phenothiazine-Sepharose and was heat-stable. Control supernatant from the incubation of membranes in the absence of thyroxine contained calmodulin, the bioactivity of which was not enhanced beyond that predicted from radioimmunoassay. Subsequent addition of thyroxine did not increase calmodulin bioactivity. Calmodulin-agarose removed calmodulin-enhancing activity from the supernatant. 3. Thus, the enhancing factor(s) appears to interact directly with calmodulin. These observations indicate that thyroid hormone promotes the release from human erythrocyte membranes of a soluble factor (or factors) which binds to calmodulin and significantly increases its bioactivity. This enhancing activity is similar to that of a calmodulin activator described in a rat model of hypertension (S.-L. Huang et al., J Clin Invest 1988; 82: 276-81).

scholarly journals Degradation of Band-3 Glycoprotein in vitro by a Protease Isolated from Human Erythrocyte Membranes

1982 ◽  
Vol 121 (2) ◽  
pp. 463-467 ◽  
Author(s):  
Anne Marianne GOLOVTCHENKO-MATSUMOTO ◽  
Isamu MATSUMOTO ◽  
Toshiaki OSAWA
Keyword(s):  
Human Erythrocyte ◽  
Band 3 ◽  
Erythrocyte Membranes ◽  
Human Erythrocyte Membranes

Effect of Aldosterone on the Human Erythrocyte Sodium-Potassium Pump in vitro

1983 ◽  
Vol 64 (2) ◽  
pp. 183-186 ◽  
Author(s):  
N. Stern ◽  
F. Beck ◽  
J. Sowers
Keyword(s):  
Atpase Activity ◽  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Ouabain Binding ◽  
Physiological Concentration ◽  
Sodium Potassium ◽  
Human Erythrocyte Membranes ◽  
Erythrocyte Sodium ◽  
Sodium Potassium Pump

1. The effects of aldosterone in vitro on the Na+,K+-dependent ATPase activity of isolated human erythrocyte membranes and on rubidium (86Rb) uptake and [3H]ouabain binding of intact erythrocytes were studied. 2. ATPase activity was nearly doubled (0.061 ± 0.006 to 0.110 ± 0.01 μmol of Pl h−1 mg−1 of protein) by the addition of a physiological concentration of aldosterone (2.7 × 10-10 mol/l). Higher concentrations had no greater effect. 3. Aldosterone had no significant effect on 86Rb uptake or [3H]ouabain binding. 4. Erythrocytes contain aldosterone at concentrations similar to that in plasma. The effect of aldosterone on ATPase is probably maximal.

Effects of phenylpropanolamine (PPA) on in vitro human erythrocyte membranes and molecular models

2011 ◽  
Vol 406 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Mario Suwalsky ◽  
Pablo Zambrano ◽  
Sigrid Mennickent ◽  
Fernando Villena ◽  
Carlos P. Sotomayor ◽  
...  
Keyword(s):  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Molecular Models ◽  
Human Erythrocyte Membranes

scholarly journals Optical-rotatory-dispersion studies of compounds related to cholesterol in liposomes and the membranes of erythrocyte ‘ghosts’

1973 ◽  
Vol 135 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Jonathan R. Green ◽  
Peter A. Edwards ◽  
Colin Green
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Erythrocyte Membranes ◽  
Optical Rotatory ◽  
Erythrocyte Ghosts ◽  
Polar Solvents ◽  
Human Erythrocyte Membranes ◽  
Do So

1. Steroid molecules containing the α,β-unsaturated oxo group in various positions were incorporated with egg phosphatidylcholine into liposomes and into human erythrocyte membranes. 2. The liposomes formed contained 0.3–0.94mol of steroid/mol of phospholipid and the steroids replaced 19–76% of the erythrocyte membrane sterol. 3. The optical rotatory dispersion (o.r.d.) spectra of the steroids in these structures were compared with those obtained in solvents of different polarity. 4. The o.r.d. spectra of cholesta-4,6-dien-3-one and 3-hydroxycholest-3-en-2-one in liposomes resembled those obtained with polar solvents such as ethanol or triethyl phosphate–water (1:1, v/v). 5. The o.r.d. spectra of 3-hydroxycholest-7-en-6-one and 3-hydroxycholest-5-en-7-one in liposomes resembled those obtained with moderately polar solvents such as dioxan. 6. The o.r.d. spectrum of 3-hydroxycholest-8(14)-en-15-one in liposomes resembled those obtained with non-polar solvents such as cyclohexane. 7. 3-Hydroxycholest-3-en-2-one did not exchange with erythrocyte membrane cholesterol, but the other steroids did do so and the o.r.d. spectra of the membranes containing them closely resembled those obtained with liposomes. 8. From the results, the position of sterol molecules with respect to the phospholipid molecules in liposomes and membranes of human erythrocyte ‘ghosts’ can be deduced.

scholarly journals Self-digestion of human erythrocyte membranes. Role of adenosine triphosphate and glutathione

1977 ◽  
Vol 164 (2) ◽  
pp. 469-472 ◽  
Author(s):  
A Brovelli ◽  
M Suhail ◽  
G Pallavicini ◽  
F Sinigaglia ◽  
C Balduini
Keyword(s):  
Chemical Composition ◽  
Adenosine Triphosphate ◽  
Human Erythrocyte ◽  
Incubation Medium ◽  
Reduced Glutathione ◽  
Human Erythrocytes ◽  
Erythrocyte Membranes ◽  
Digestion Process ◽  
Human Erythrocyte Membranes

Intact human erythrocytes incubated at 37 degrees C, pH7.4, release a sialoglycopeptide similar in its chemical composition, immunological and aggregation properties to the glycopeptide released by isolated ‘ghost’ membranes. The presence of ATP or reduced glutathione at physiological concentrations in the incubation medium of ‘ghost’ membranes inhibits this self-digestion process.

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