scholarly journals Identification of the aspartic proteinases from human erythrocyte membranes and gastric mucosa (slow-moving proteinase) as catalytically equivalent to cathepsin E

1988 ◽  
Vol 254 (3) ◽  
pp. 895-898 ◽  
Author(s):  
R A Jupp ◽  
A D Richards ◽  
J Kay ◽  
B M Dunn ◽  
J B Wyckoff ◽  
...  
Keyword(s):  
Gastric Mucosa ◽  
Human Erythrocyte ◽  
Ph Value ◽  
Polyacrylamide Gel Electrophoresis ◽  
Erythrocyte Membranes ◽  
Human Gastric Mucosa ◽  
Aspartic Proteinases ◽  
Cathepsin E ◽  
Activity Measurements ◽  
Human Erythrocyte Membranes

Three aspartic proteinases with similar Mr values (approx. 80,000) but from distinct sources (human gastric mucosa, human erythrocyte membranes and rat spleen) were shown to have immunological cross-reactivity and comparable mobilities when subjected to polyacrylamide-gel electrophoresis under non-denaturing conditions. Kinetic parameters (kcat, Km and Ki) were determined for the interactions of the three enzymes with two synthetic chromogenic substrates and five inhibitors (naturally occurring and synthetic). On this basis it would appear that all of the enzymes should be considered equivalent to cathepsin E. pH-activity measurements indicated that the aspartic proteinase that originated from the erythrocyte membranes retained activity at a higher pH value than either of its readily soluble counterparts.

scholarly journals Metabolic dependence of protein arrangement in human erythrocyte membranes. I. Analysis of spectrin-rich complexes in ATP-depleted red cells

Blood ◽  
1978 ◽  
Vol 51 (3) ◽  
pp. 385-395 ◽  
Author(s):  
J Palek ◽  
SC Liu ◽  
LM Snyder
Keyword(s):  
Human Erythrocyte ◽  
Polyacrylamide Gel Electrophoresis ◽  
Band 3 ◽  
Atp Depletion ◽  
Red Cells ◽  
Erythrocyte Membranes ◽  
Red Cell ◽  
Aerobic Conditions ◽  
Spontaneous Formation ◽  
Human Erythrocyte Membranes

Abstract The discocyte-echinocyte transformation and the decrease in deformability associated with red cell ATP depletion have been attributed to changes in the physical properties of spectrin and actin, membrane proteins located at the membrane-cytosol interface. We investigated the spontaneous formation of spectrin-rich complexes in human erythrocyte membranes, employing two-dimensional SDS- polyacrylamide gel electrophoresis. Membranes of red cells depleted in ATP under aerobic conditions exhibited (1) an increase in components 4.5 and 8 and globin subunits, (2) a spontaneous formation of heterodimers of spectrin 1 + 2 and spectrin 2 + component 4.9, and (3) a large molecular weight (greater than 10(6) daltons) protein complex with a high spectrin to band 3 ratio. These complexes were dissociated with dithiothreitol and were prevented by anaerobic incubation or the maintenance of red cell ATP and GSH levels with glucose, adenine, and inosine. The complexes 1 + 2 and 2 + 4.9 were also seen in acetylphenylhydrazine-treated, glucose-6-phosphate dehydrogenase- deficient fresh erythrocytes that showed marked GSH depletion but preserved greater than 70% of the original ATP level. However, membranes of these cells did not contain the greater 10(6) dalton aggregate with a high spectrin to band 3 ratio. We concluded that the formation of the latter complex results from rearrangement of spectrin and other polypeptides in membranes of ATP-depleted red cells. Under aerobic conditions, the rearranged proteins undergo spontaneous intermolecular crosslinkings through disulfide couplings.

scholarly journals Protein Kinase Activity of Human Erythrocyte Membranes in Friedreich's Ataxia

1980 ◽  
Vol 7 (4) ◽  
pp. 425-427
Author(s):  
P. Wong ◽  
A. Barbeau
Keyword(s):  
Protein Kinase ◽  
Human Erythrocyte ◽  
Kinase Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Friedreich’S Ataxia ◽  
Friedreich's Ataxia ◽  
Erythrocyte Membranes ◽  
Protein Kinase Activity ◽  
Before And After ◽  
Human Erythrocyte Membranes

SUMMARY:Proteins of human erythrocyte membranes of Friedrich's ataxia patients and controls were examined by SDS-polyacrylamide gel electrophoresis before and after reduction withβ-mercaptoethanol. No difference could be detected in the composition of their state of aggregation. The protein kinase activity of human erythrocyte membranes of eleven Friedreich's ataxia patients and six controls was determined. No difference in their protein kinase activity could be detected. These results are discussed with respect to an involvement of a generalized membrane defect in Friedreich's ataxia.

Variability of Conductivity Changes in Black Phosphatidylserine Membranes Induced by Proteins from Erythrocyte Membranes

1977 ◽  
Vol 32 (5-6) ◽  
pp. 375-378 ◽  
Author(s):  
H. Bleuel ◽  
G. Wiedner ◽  
D. Schubert
Keyword(s):  
Electrical Conductivity ◽  
Human Erythrocyte ◽  
Sodium Phosphate ◽  
Protein Concentration ◽  
Ph Value ◽  
Erythrocyte Membranes ◽  
Membrane Conductivity ◽  
Protein Subunits ◽  
Conductivity Increase ◽  
Human Erythrocyte Membranes

Abstract The electrical conductivity of black phosphatidylserine membranes, in solutions of 100 mм NaCl, 10 mм sodium phosphate (pH 7.1), is strongly increased by the intrinsic proteins (“strongly bound” protein fraction) from human erythrocyte membranes. The magnitude of the conductivity increase is highly dependent on the maximum pH-value pH* used during the preparation of the protein (8.0≦ pH* ≦11.8). For each pH*, membrane conductivity λf and protein concentration c are linked by the equation λf=k·-cs, k and s being functions only of pH*. The value of s varies between 1.0 (pH* 8) and 4.0 (pH* 10). It is assumed that the protein-induced conducting sites, at least for protein pretreatment at pH* ≦ 10, are assembled from four protein subunits. The incorporation of the subunits into the lipid bilayer is supposed to occur either as the final tetramer (pH* 8) or as monomers (pH* 10) and possibly dimers (pH* around 9).

The nature of human erythrocyte receptors for Neisseria gonorrhoeae

1982 ◽  
Vol 28 (2) ◽  
pp. 219-222 ◽  
Author(s):  
G. M. Wiseman ◽  
P. McNicol
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Human Erythrocyte ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein Band ◽  
Band 3 ◽  
Erythrocyte Membranes ◽  
Glycophorin A ◽  
Receptor Sites ◽  
Human Erythrocyte Membranes ◽  
Sepharose 4B

Normal and trypsinized human erythrocyte membranes were used as a model in the study of host cell receptors for Neisseria gonorrhoeae. Receptor sites were identified by adherence inhibition assays of fractions of membranes eluted from polyacrylamide gel electrophoresis columns. Results indicated that inhibition of gonococcus T1 and T4 adherence was associated with erythrocyte protein bands 3 and 4 and glycophorin A, the major sialoglycoprotein. Further investigation revealed that band 3 preparations isolated by affinity chromatography on concanavalin A – Sepharose 4B columns continued to inhibit T1 adherence to erythrocytes but did not inhibit adherence of T4 organisms. It is suggested that protein band 3 is the receptor on erythrocytes for T1 gonococci and that glycophorin A may be the receptor for T4 cells.

scholarly journals Metabolic dependence of protein arrangement in human erythrocyte membranes. I. Analysis of spectrin-rich complexes in ATP-depleted red cells

Blood ◽  
1978 ◽  
Vol 51 (3) ◽  
pp. 385-395
Author(s):  
J Palek ◽  
SC Liu ◽  
LM Snyder
Keyword(s):  
Human Erythrocyte ◽  
Polyacrylamide Gel Electrophoresis ◽  
Band 3 ◽  
Atp Depletion ◽  
Red Cells ◽  
Erythrocyte Membranes ◽  
Red Cell ◽  
Aerobic Conditions ◽  
Spontaneous Formation ◽  
Human Erythrocyte Membranes

The discocyte-echinocyte transformation and the decrease in deformability associated with red cell ATP depletion have been attributed to changes in the physical properties of spectrin and actin, membrane proteins located at the membrane-cytosol interface. We investigated the spontaneous formation of spectrin-rich complexes in human erythrocyte membranes, employing two-dimensional SDS- polyacrylamide gel electrophoresis. Membranes of red cells depleted in ATP under aerobic conditions exhibited (1) an increase in components 4.5 and 8 and globin subunits, (2) a spontaneous formation of heterodimers of spectrin 1 + 2 and spectrin 2 + component 4.9, and (3) a large molecular weight (greater than 10(6) daltons) protein complex with a high spectrin to band 3 ratio. These complexes were dissociated with dithiothreitol and were prevented by anaerobic incubation or the maintenance of red cell ATP and GSH levels with glucose, adenine, and inosine. The complexes 1 + 2 and 2 + 4.9 were also seen in acetylphenylhydrazine-treated, glucose-6-phosphate dehydrogenase- deficient fresh erythrocytes that showed marked GSH depletion but preserved greater than 70% of the original ATP level. However, membranes of these cells did not contain the greater 10(6) dalton aggregate with a high spectrin to band 3 ratio. We concluded that the formation of the latter complex results from rearrangement of spectrin and other polypeptides in membranes of ATP-depleted red cells. Under aerobic conditions, the rearranged proteins undergo spontaneous intermolecular crosslinkings through disulfide couplings.

scholarly journals The effect of RNA on cathepsin E from human erythrocyte membranes.

1991 ◽  
Vol 55 ◽  
pp. 308
Author(s):  
Eiko Ueno ◽  
Yuzo Kato ◽  
Mitsue Ezaki ◽  
Kenji Yamamoto
Keyword(s):  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Cathepsin E ◽  
Human Erythrocyte Membranes

scholarly journals Interaction of platelet plasma membranes with thrombin-activated platelets

Blood ◽  
1981 ◽  
Vol 57 (2) ◽  
pp. 305-312 ◽  
Author(s):  
HR Prasanna ◽  
HH Edwards ◽  
DR Phillips
Keyword(s):  
Human Erythrocyte ◽  
Plasma Membranes ◽  
Membrane Binding ◽  
Human Platelets ◽  
Platelet Membrane ◽  
Erythrocyte Membranes ◽  
Functional Sites ◽  
Activated Platelets ◽  
Platelet Membranes ◽  
Human Erythrocyte Membranes

Abstract This study described the binding of platelet plasma membranes to either control or thrombin-activated platelets. Glycoproteins in plasma membranes isolated from human platelets were labeled by oxidation with periodate followed by reduction with [3H]NaBH4. Labeled membranes were incubated with either control or thrombin-activated platelets. The amount of membranes bound was measured by separating platelets with bound membranes from solution by rapid centrifugation through 27% sucrose and determining the amount of radioactivity associated with platelets. Five- to sevenfold more membranes bound to thrombin- activated platelets than to control platelets. This enhanced binding of labeled membranes was completely inhibited by an excess of unlabeled platelet membranes. Human erythrocyte membranes had little affinity for either washed or thrombin-activated platelets and therefore did not compete for platelet-membrane binding. Binding of platelet membranes to thrombin-treated platelets was inhibited by prior incubation of the platelets with PGI2 suggesting that the enhanced binding of membranes was to activated platelets. This study demonstrates that the purified platelet membranes have functional sites that can mediate membrane binding to platelets and that quantitation of membrane binding appears to reflect the increased aggregation capability of activated platelets.

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