scholarly journals The iron-binding properties of hen ovotransferrin

1978 ◽  
Vol 173 (2) ◽  
pp. 533-539 ◽  
Author(s):  
J Williams ◽  
R W Evans ◽  
K Moreton
Keyword(s):  
Binding Sites ◽  
Gel Electrophoresis ◽  
Iron Binding ◽  
Alkaline Ph ◽  
Binding Properties ◽  
Partially Saturated ◽  
Isotope Method ◽  
Electrophoresis Method ◽  
Terminal Site ◽  
Double Isotope

1. The distribution of iron between the two iron-binding sites in partially saturated ovotransferrin was studied by labelling with 55Fe and 59Fe and by gel electrophoresis in a urea-containing buffer. 2. When iron is added in the form of chelate complexes at alkaline pH, binding occurs preferentially at the N-terminal binding site. In acid, binding occurs preferentially at the C-terminal site. 3. When simple iron donors (ferric and ferrous salts) are used the metal is distributed at random between the binding sites, as judged by the gel-electrophoresis method. The double-isotope method shows a preference of ferrous salts for the N-terminal site. 4. Quantitative treatment of the results of double-isotope labelling suggests that in the binding of iron to ovotransferrin at alkaline pH co-operative interactions between the sites occur. These interactions are apparently absent in the displacement of copper and in the binding of iron at acid pH.

scholarly journals The effect of salt concentration on the iron-binding properties of human transferrin

1982 ◽  
Vol 201 (3) ◽  
pp. 527-532 ◽  
Author(s):  
J Williams ◽  
N D Chasteen ◽  
K Moreton
Keyword(s):  
Salt Concentration ◽  
Binding Sites ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Iron Binding ◽  
Iron Release ◽  
Equilibrium Conditions ◽  
Binding Properties ◽  
Kinetics Of ◽  
Terminal Site

The salt dependence of the iron-binding properties of transferrin was studied by urea/polyacrylamide-gel electrophoresis. The distribution of iron between the N-terminal and C-terminal binding sites under equilibrium conditions and the rates of release of iron from the two sites were studied. It was found that salt increases the thermodynamic stability of iron binding in the N-terminal site relative to the C-terminal site. Similar behaviour is observed for the kinetics of iron release, where salt retards the rate of removal of iron from the N-terminal site but facilitates removal from the C-terminal site.

scholarly journals The distribution of iron between the metal-binding sites of transferrin human serum

1980 ◽  
Vol 185 (2) ◽  
pp. 483-488 ◽  
Author(s):  
J Williams ◽  
K Moreton
Keyword(s):  
Human Serum ◽  
Metal Binding ◽  
Binding Sites ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Iron Binding ◽  
Metal Binding Sites ◽  
Fresh Serum ◽  
Marked Preference ◽  
Terminal Site

The Makey & Seal [(1976) Biochim. Biophys. Acta 453, 250-256] method of polyacrylamide-gel electrophoresis in buffer containing 6 M-urea was used to determine the distribution of iron between the N-terminal and C-terminal iron-binding sites of transferrin in human serum. In fresh serum the two sites are unequally occupied; there is preferential occupation of the N-terminal site. On incubation of the serum at 37 degrees C the preference of iron for the N-terminal site becomes more marked. On storage of serum at −15 degrees C the iron distribution changes so that there is a marked preference for the C-terminal site. Dialysis of serum against buffer at pH 7.4 also causes iron to be bound much more strongly by the C-terminal than by the N-terminal site. The original preference for the N-terminal site can be resroted to the dialysed serum by addition of the diffusible fraction.

EXTRACELLULAR CALCIUM AND PLATELET GLYCOPROTEINS

1987 ◽  
Author(s):  
I Jabbal-Gill ◽  
G I Johnston ◽  
S Heptinstall
Keyword(s):  
Binding Sites ◽  
Gel Electrophoresis ◽  
Marked Decrease ◽  
Polyacrylamide Gel Electrophoresis ◽  
Specific Monoclonal Antibody ◽  
Alkaline Ph ◽  
Membrane Glycoproteins ◽  
Crossed Immunoelectrophoresis ◽  
The Stability ◽  
Ca Depletion

Platelet membrane glycoproteins lib and Ilia form Ca++-dependent heterodimer complexes that contain binding sites for fibrinogen and therefore are relevant to the ability of platelets to aggregate together. In this study we investigated the effects of extracellular Ca++ on the stability and expression of IIb-IIIa complexes using a IIb-IIIa complex-specific monoclonal antibody M148. Its specificity was examined using crossed immunoelectrophoresis: the antibody reacted only with intact IIb-IIIa complexes and not with either glycoprotein alone.SDS-polyacrylamide gel electrophoresis of immunoprecipitates of soluble glycoproteins that interacted with Ml48 showed that lib and Ilia were present as complexes in Ca++-depleted media at 25°C, pH7.4. However, Ca++-depletion at 37°C, pH7.4 or 37°C, pH8.7 or 25°C, pH8.7 caused dissociation of the complexThe effect of extracellular Ca++ on the expression of IIb-Illa complexes on the surface of intact platelets was studied by a technique which is based upon indirect binding of M148 using a fluorescent- labelled second antibody (FITC-RAM) and measuring the fluorescence per platelet using the FACS IV cytofluorometer. Intact platelets were incubated in Ca++-depleted media at 25°C, pH7.4 or 37°C, pH7.4 either (i) prior to or (ii) after adding M148. At 25°C increased M148-binding was observed, compared to the value prior to Ca++-depletion. This increased binding could be reversed by adding Ca++ back to the preparation. Under condition (i) at 37°C a marked decrease in M148 binding was observed, which could not be reversed by restoring Ca++, while under condition (ii) at 37°C the results were the same as at 25°C.Our studies demonstrate that (a) Ca++-depletion at 37°C and/or alkaline pH causes dissociation of the Ilb-IIIa complex (b) Ca++ depletion at 25°C possibly alters distribution of the complexes thereby increasing their availability to the antibody and (c) M148 prevents the dissociation of complexes in Ca++-depleted media at 37°C, possibly by holding lib and Ilia together

scholarly journals Vertebrate lectins, Comparison of properties of beta-galactoside-binding lectins from tissues of calf and chicken.

1979 ◽  
Vol 81 (3) ◽  
pp. 528-537 ◽  
Author(s):  
E B Briles ◽  
W Gregory ◽  
P Fletcher ◽  
S Kornfeld
Keyword(s):  
Binding Sites ◽  
Gel Electrophoresis ◽  
Cellular Localization ◽  
Polyacrylamide Gel Electrophoresis ◽  
Thiol Group ◽  
Cross Reactivity ◽  
Cytoplasmic Localization ◽  
Binding Properties ◽  
Fluorescence Studies ◽  
Species Specific

Beta-galactoside-binding lectins were isolated from various calf tissues and from chicken hearts by affinity chromatography on asialofetuin-Sepharose, and were compared with respect to biochemical characteristics, binding properties, antigenic cross-reactivity, and cellular localization. The lectins are all thiol group-requiring, divalent cation-independent dimers, of apparent monomer mol wt 12,000 (calf lectins) or 13,000 (chicken lectin), and acidic pI. The calf lectins appear essentially identical by dodecyl sulfate-polyacrylamide gel electrophoresis, isoelectric focusing, amino acid composition, and radioimmunoassay, while the chicken lectin is distinctly different by these criteria. However, all of the lectins competed for the same binding sites on rabbit erythrocytes, and could be inhibited by the same saccharide haptens (notably lactose and thiodigalactoside). Immuno-fluorescence studies on several cultured cell lines revealed that the bovine and chicken lectins had primarily an intracellular cytoplasmic localization. The beta-galactoside-binding lectins of vertebrates appear to be species-specific rather than tissue-specific.

EFFECT OF HEPARIN ON THE CORTICOSTERONE SECRETION RATE WITH A DESCRIPTION OF THE DOUBLE ISOTOPE METHOD USED

1967 ◽  
Vol 56 (1_Suppl) ◽  
pp. S140 ◽  
Author(s):  
A. F. Casparie ◽  
Th. J. Benraad ◽  
P. W. C. Kloppenborg ◽  
C. L. H. Majoor
Keyword(s):  
Secretion Rate ◽  
Isotope Method ◽  
Corticosterone Secretion ◽  
Double Isotope

Comparative Two-Dimensional Gel Electrophoresis of Trypanosoma cruzi Mammalian-Stage Forms in an Alkaline pH Range

2015 ◽  
Vol 22 (12) ◽  
pp. 1066-1075 ◽  
Author(s):  
Adriana Magalhães ◽  
Rayner Queiroz ◽  
Izabela Bastos ◽  
Jaime Santana ◽  
Marcelo Sousa ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Gel Electrophoresis ◽  
Two Dimensional ◽  
Alkaline Ph ◽  
Two Dimensional Gel Electrophoresis ◽  
Ph Range

scholarly journals Development of a highly sensitive three-dimensional gel electrophoresis method for characterization of monoclonal protein heterogeneity

2013 ◽  
Vol 438 (2) ◽  
pp. 117-123 ◽  
Author(s):  
Keiichi Nakano ◽  
Shogo Tamura ◽  
Kohei Otuka ◽  
Noriyasu Niizeki ◽  
Masahiko Shigemura ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Three Dimensional ◽  
Monoclonal Protein ◽  
Highly Sensitive ◽  
Electrophoresis Method
Sign in / Sign up

Export Citation Format

Share Document