Competition between glycoprotein hormones and horseradish peroxidase for mannose-specific binding sites in cells of endocrine organs

1983 ◽  
Vol 78 (3) ◽  
pp. 289-302 ◽  
Author(s):  
W. Straus
Keyword(s):  
Horseradish Peroxidase ◽  
Binding Sites ◽  
Specific Binding ◽  
Glycoprotein Hormones ◽  
Specific Binding Sites ◽  
Endocrine Organs ◽  
In Cells

scholarly journals Mannose-specific binding sites for horseradish peroxidase in various cells of the rat.

1983 ◽  
Vol 31 (1) ◽  
pp. 78-84 ◽  
Author(s):  
W Straus
Keyword(s):  
Mast Cells ◽  
Horseradish Peroxidase ◽  
Binding Sites ◽  
Specific Binding ◽  
Cell Types ◽  
Sinusoidal Cells ◽  
Binding Reaction ◽  
Specific Binding Sites ◽  
Liver Sinusoidal Cells ◽  
Endogenous Lectins

Mannose-specific binding sites for horseradish peroxidase (HRP) were studied in fixed sections of various tissues by a method reported previously. Liver sinusoidal cells, mast cells of lymph nodes, and alveolar macrophages of the lung and skin fibroblasts were main cell types showing mannose-specific binding of HRP. Macrophages, fibroblasts, and mast cells in the connective tissue of other organs also showed the reaction. However, macrophages of the spleen, and cultured 3T3 cells and L-cells did not give the reaction. The specificities of the binding reaction were studied by determining the approximate concentrations of competing sugars that suppressed the specific binding of HRP. It was found that the endogenous lectins in macrophages, fibroblasts, mast cells, and liver sinusoidal cells showed similar specificities toward various carbohydrates. D-Mannose and L-fucose had the highest affinity toward the lectins (competing ability for the binding of HRP). D-Mannose-6-phosphate, N-acetyl-D-glucosamine, D-glucose, D-ribose, and D-arabinose showed intermediate affinity, whereas D-xylose and D-galactose showed low affinity. Polymerized mannose in mannan and glycoproteins rich in mannose groups (invertase and ribonuclease B) showed much higher affinity to the binding sites than free mannose.

scholarly journals Specific binding sites for progesterone and 17beta-estradiol in cells of Triticum aestivum L.

2008 ◽  
Vol 55 (4) ◽  
pp. 707-711 ◽  
Author(s):  
Anna Janeczko ◽  
Bogusława Budziszewska ◽  
Andrzej Skoczowski ◽  
Małgorzata Dybała
Keyword(s):  
Triticum Aestivum ◽  
Binding Sites ◽  
Radioligand Binding ◽  
Steroid Receptors ◽  
Specific Binding ◽  
Triticum Aestivum L ◽  
Specific Binding Sites ◽  
Steroid Binding Proteins ◽  
Steroid Binding ◽  
In Cells

The presence and location of specific binding sites for progesterone and 17beta-estradiol in cells of wheat were estimated using radioligand binding assay. Membrane and cytosolic fractions of non-vernalized and vernalized plants were tested using tritium-labelled ligands. Specific binding of [(3)H]progesterone and [(3)H]17beta-estradiol occurs in wheat cells. The binding sites are located in membranes and in the cytosol. Specific binding of [(3)H]17beta-estradiol is higher in the membranes than in the cytosol. Specific binding of both ligands in the cytosolic fraction is higher in vernalized plants than in non-vernalized ones. The possibility of the occurrence of steroid binding proteins specific for progesterone and 17beta-estradiol, putative steroid receptors for these steroids in Triticum aestivum L., is discussed.

scholarly journals Specific Binding of Rubidium in Chlorella

1962 ◽  
Vol 45 (5) ◽  
pp. 959-977 ◽  
Author(s):  
Dan Cohen
Keyword(s):  
Active Transport ◽  
Binding Sites ◽  
Specific Binding ◽  
High Concentration ◽  
External Concentration ◽  
Specific Binding Sites ◽  
Dense Suspension ◽  
Concentration Of Ions ◽  
The Individual ◽  
A Site

Specific binding sites for potassium, which may be components of the carriers for active transport for K in Chlorella, were characterized by their capacity to bind rubidium. A dense suspension was allowed to take up Rb86 from a low concentration of Rb86 and a high concentration of ions which saturate non-specific sites. The amount bound was derived from the increase in the external concentration of Rb86 following addition of excess potassium. The sites were heterogeneous. The average affinity of Rb and various other ions for the sites was determined by plotting the degree of displacement of Rb86 against log molar concentration of the individual ions. Interpolation gave the concentration for 50 per cent displacement of Rb, which is inversely related to affinity. The order of affinity was not changed when the cells were frozen, or boiled either in water or in 70 per cent ethanol. The affinity is maximal for ions with a crystalline radius of 1.3 to 1.5 A and a high polarizability, and is not related to the hydrated radius or valency. It is suggested that binding groups in a site are rigidly arranged, the irregular space between them being 2.6 to 3.0 A across, so that affinity is high for ions of this diameter and high polarizability.

Studies of the uptake of macromolecules by cells. I. Uptake of proteins by cells of the Ehrlich–Lettré ascites carcinoma

1968 ◽  
Vol 46 (12) ◽  
pp. 1443-1450 ◽  
Author(s):  
Y. C. Choi ◽  
E. R. M. Kay
Keyword(s):  
Nucleic Acid ◽  
Cell Membrane ◽  
Binding Sites ◽  
Specific Binding ◽  
Protein Uptake ◽  
Specific Binding Sites ◽  
Model Protein ◽  
Uptake Process ◽  
Kinetics Of ◽  
Protein Treatment

The uptake of protein by cells of the Ehrlich–Lettré ascites carcinoma was characterized kinetically by using hemoglobin as a model protein. An attempt was made to show that the process is not an artefact due to nonspecific adsorption of protein to the cell membrane. The kinetics of the uptake process suggested that an interaction exists between the exogenous protein and specific binding sites on the membrane. Acetylation of hemoglobin enhanced the rate of uptake of this protein. Treatment of cells with neuraminidase, phospholipase A, and Pronase resulted in an inhibition of protein uptake. The experimental evidence for the uptake of hemoglobin was supported by evidence that L-serine-U-14C-labelled hemoglobin is transported into the cytoplasm and utilized subsequently, resulting in labelling of the nucleic acid nucleotides.

Sign in / Sign up

Export Citation Format

Share Document