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Evidence for negative cooperativity in human erythrocyte sugar transport
Biochimica Et Biophysica Acta
|December 21, 1981
Summary
This study reveals negative cooperativity in glucose transport, consistent with the allosteric pore model. This model explains the transport protein
Area of Science:
- Biochemistry
- Molecular Biology
- Membrane Transport
Background:
- Glucose transport across cell membranes is crucial for cellular metabolism.
- Understanding the kinetics and mechanisms of glucose transporters is essential for various biological processes.
Purpose of the Study:
- To investigate the kinetic properties of D-glucose transport.
- To validate the allosteric pore model for glucose transport.
- To explore the role of negative cooperativity in the transport mechanism.
Main Methods:
- Kinetic analysis of D-glucose exchange influx over a range of concentrations.
- Derivation and application of allosteric pore model equations.
- Analysis of exchange inhibition and mixed infinite-trans uptake experiments.
- Investigation of fluorodinitrobenzene (FDNB) effects on glucose transport inhibition.
Main Results:
- Two affinity constants (2.27 and 26.0 mM) for D-glucose influx indicate negative cooperativity.
- The allosteric pore model accurately describes transport data, including inhibition by other sugars.
- FDNB treatment alters D-glucose inhibition constants, suggesting an effect on the transporter's internal gate.
Conclusions:
- The allosteric pore model with negative cooperativity provides a robust framework for understanding glucose transport kinetics.
- Inhibition patterns and kinetic parameters support the proposed model of transporter function.
- Specific chemical modifications, like FDNB treatment, can modulate transporter activity by affecting subunit interactions.