scholarly journals Characterization of peptide fluxes into human erythrocytes. A proton-n.m.r. study

1990 ◽  
Vol 267 (1) ◽  
pp. 141-147 ◽  
Author(s):  
J E Odoom ◽  
I D Campbell ◽  
J C Ellory ◽  
G F King
Keyword(s):  
High Capacity ◽  
Transport Processes ◽  
Human Erythrocytes ◽  
Peptide Hydrolysis ◽  
Simple Diffusion ◽  
Analytical Technique ◽  
Peptidase Inhibitor ◽  
Diffusive Fluxes ◽  
Dipeptide Uptake

A new protocol for measuring cellular uptake of dipeptides was developed in which the problem of peptide hydrolysis is obviated by introduction into the cell suspension of a membrane-permeant peptidase inhibitor. The uptake of unlabelled dipeptide is readily monitored so long as some analytical technique is available for measuring the intracellular peptide concentration; in this study we used n.m.r. spectroscopy. Using this protocol, we demonstrated that dipeptide uptake by human erythrocytes occurs by simple diffusion through the lipid bilayer and not via a high-capacity protein-mediated transport system. Substantiating evidence includes demonstration that: (a) the fluxes are slow compared with known protein-mediated transport processes in human erythrocytes; (b) the uptake is not stereospecific; (c) the uptake does not display saturation kinetics; (d) the fluxes are significantly enhanced by butanol; (e) a distinct correlation exists between the size-corrected permeability coefficients of the dipeptides and their calculated n-octanol/water partition coefficients. It is calculated that under normal physiological conditions the diffusive fluxes of circulating plasma peptides into human erythrocytes are too small for these cells to play a significant role in dipeptide catabolism.

Characterization of the glucose transporter from human erythrocytes

1978 ◽  
Vol 8 (4) ◽  
pp. 447-453 ◽  
Author(s):  
David C. Sogin ◽  
Peter C. Hinkle
Keyword(s):  
Glucose Transporter ◽  
Human Erythrocytes

scholarly journals Purification and characterization of cystatin from duck egg white.

1995 ◽  
Vol 42 (3) ◽  
pp. 351-356 ◽  
Author(s):  
M Warwas ◽  
J Gburek ◽  
J Osada ◽  
K Gołab
Keyword(s):  
Egg White ◽  
Amino Acid Sequences ◽  
Size Exclusion ◽  
Molecular Forms ◽  
Sds Page ◽  
Peptidase Inhibitor ◽  
Size Exclusion Hplc ◽  
Duck Egg ◽  
Chicken Cystatin

It is the second peptidase inhibitor, after ovostatin, which showing the same antipapain activity in egg white in different avian species implies differences in amino-acid sequences. Cystatin from duck egg white was purified by carboxymethylpapain affinity chromatography and size-exclusion HPLC. The purified inhibitor which showed partial identity in the immunodiffusion test with chicken egg white cystatin, had an apparent molecular mass of 9.3 kDa as determined by SDS/PAGE. IEF analysis revealed five molecular forms of pI in the range 7.8-8.4. The obtained cystatin was neither glycosylated nor phosphorylated as it is in the case of chicken cystatin. The determined Ki (0.005 +/- 0.001 nM) was similar to that reported for human and chicken cystatin C.

scholarly journals Vortex dynamics under pulsatile flow in axisymmetric constricted tubes

2020 ◽  
Vol 12 ◽  
pp. 120002
Author(s):  
Nicasio Barrere ◽  
Javier Brum ◽  
Alexandre L'her ◽  
Gustavo L. Sarasúa ◽  
Cecilia Cabeza
Keyword(s):  
Flow Pattern ◽  
Pulsatile Flow ◽  
Scaling Law ◽  
Transport Processes ◽  
Turbulent Regime ◽  
Dimensionless Variable ◽  
Image Velocimetry ◽  
Pulsatile Flows ◽  
Rigid Model

Improved understanding of how vortices develop and propagate under pulsatile flow can shed important light on the mixing and transport processes occurring in such systems, including the transition to turbulent regime. For example, the characterization of pulsatile flows in obstructed artery models serves to encourage research into flow-induced phenomena associated with changes in morphology, blood viscosity, wall elasticity and flow rate. In this work, an axisymmetric rigid model was used to study the behaviour of the flow pattern with varying degrees constriction  ($d_0$) and mean Reynolds ($\bar{Re}$) and Womersley numbers ($\alpha$). Velocity fields were obtained experimentally using Digital Particle Image Velocimetry and generated numerically. For the acquisition of data, $\bar{Re}$ was varied from 385 to 2044, $d_0$ was 1.0 cm and 1.6 cm, and $\alpha$ was varied from 17 to 33 in the experiments and from 24 to 50 in the numerical simulations. Results for the Reynolds number considered showed that the flow pattern consisted of two main structures: a central jet around the tube axis and a recirculation zone adjacent to the inner wall of the tube, where vortices shed. Using the vorticity fields, the trajectory of vortices was tracked and their displacement over their lifetime calculated. The analysis led to a scaling law equation for maximum vortex displacement as a function of a dimensionless variable dependent on the system parameters Re and $\alpha$.

Purification and characterization of esterases D1 and D2 from human erythrocytes. Evidence that they are monomers

1985 ◽  
Vol 153 (2) ◽  
pp. 217-222 ◽  
Author(s):  
Kiyosato MATSUO ◽  
Kunihiko KOBAYASHI ◽  
Keiji HAGIWARA ◽  
Tadashi KAJII
Keyword(s):  
Human Erythrocytes ◽  
Purification And Characterization

Characterization of step-edge barrier crossing of para-sexiphenyl on the ZnO (101̄0) surface

2016 ◽  
Vol 18 (36) ◽  
pp. 25329-25341 ◽  
Author(s):  
Karol Palczynski ◽  
Philipp Herrmann ◽  
Georg Heimel ◽  
Joachim Dzubiella
Keyword(s):  
Thin Film ◽  
Mass Transport ◽  
Organic Molecules ◽  
Optoelectronic Devices ◽  
Thin Film Deposition ◽  
Essential Elements ◽  
Transport Processes ◽  
Film Deposition ◽  
Conjugated Organic Molecules

Mass transport processes of conjugated organic molecules (COMs) on inorganic surfaces are essential elements in thin film deposition for hybrid optoelectronic devices.

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