Written in English
|The Physical Object|
|Number of Pages||134|
The D-glucose transporter in the human erythrocyte membranes was photoaffinity-labeled with (/sup 3/H)cytochalasin B and solubilized with -glucopyranoside (octyl glucoside). (/sup 3/H)Cytochalasin B-bound proteins were further isolated by using Sephadex G chromatography. In human erythrocytes, cytochalasin B binding was inhibited dose-dependently by either nicotinamide or D-glucose, and cytochalasin B depressed the uptake of both nicotinamide and 2-deoxy-D-glucose. (A) Circular dichroism spectra of a preparation of the purified glucose transport protein of human erythrocyte membranes before and after the addition of D-glucose. The protein was reconstituted in its endogenous lipids, suspended in 5 mM phosphate buffer, pH , at 22°; protein concentration: 1 mg/ml ( x M); D-glucose was added to a Cited by: 9. D- glucose) c arrier in human erythrocyte by GLUT1. proteins carrier is proposed to exist in one of two conformation, with a binding site for glucose facing either outside or in.
Glycation of human erythrocyte membrane proteins was induced by incubation in vitro with high concentrations (80 mM or mM) of D-glucose for 3 or 6 days. GLUT1-mediated, passive d-glucose transport in human erythrocytes is asymmetric. Vmax and Km(app) for d-glucose uptake at 4 °C are fold lower than Vmax and Km(app) for d-glucose export. Transport asymmetry is not observed for GLUT1-mediated 3-O-methylglucose transport in rat, rabbit, and avian erythrocytes and rat adipocytes where Vmax for sugar uptake and exit are identical. Human erythrocyte hexose transfer is mediated by the glucose transport protein GLUT1 and is characterized by a complexity that is unexplained by available hypotheses for carrier-mediated sugar transport [Cloherty, E. K., Heard, K. S., and . The penetration of D-[14C] glucose into human red blood cells (RBCs) features kinetic parameters which are readily distinguishable from passive permeation. It would be expected to require activation energy above 80 kJ/mol for permeation of glucose with five hydroxyls capable of forming hydrogen bonds, but the measured activation energy is approximately 16 kJ/mol.
the glucose transport protein from human erythrocytes by FT-IR spectroscopy and compare this with the predictions of the structure discussed above. We also investigate the mag- nitude of the conformational changes associated with glucose transport. A preliminary study . Pre-steady-state uptake of D-glucose by the human erythrocyte is inconsistent with a circulating carrier mechanism January Biochimica et Biophysica Acta (2) Tryptic digestion has been used to investigate the conformational changes associated with substrate translocation by the human erythrocyte glucose transporter. The effects of substrates and inhibitors of transport on the rates of tryptic cleavage at the cytoplasmic surface of the membrane have confirmed previous observations that this protein can adopt at least two conformations. Phosphorylation of the human erythrocyte glucose transporter by protein kinase C: Localization of the site of in vivo and in vitro phosphorylation. International Journal of Biochemistry , 21 (7), DOI: /X(89) Anthony Carruthers. Hexose Transport Across Human Erythrocyte Membranes.