Conformational and functional properties of hemoglobin in perturbed solvent: Kinetics of O2 release

✍ Scribed by Lorenzo Cordone; Antonio Cupane; Sandro L. Fornili

• Book ID: 102762528
• Publisher: Wiley (John Wiley & Sons)
• Year: 1983
• Tongue: English
• Weight: 872 KB
• Volume: 22
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360220706

✦ Synopsis

We studied the kinetics of 0 2 release by oxyhemoglobin caused by sodium dithionite, in the presence and in the absence of organic cosolvents (monohydric alcohols and formamide) at 10°C. This study was performed by using standard stopped-flow techniques coupled with microprocessor-based data acquisition. We have fitted the experimental data to a mathematical expression obtained on the basis of a two-state model that takes into account the ki- netic heterogeneity between aand @chains and the presence of cub-dimers in oxyhemoglobin solutions. Results indicate that the cosolvents mainly affect the allosteric parameter L , i.e., the T F! R conformational equilibrium of hemoglobin, leaving the intrinsic deoxygenation rates of both R and T states almost unaltered. The L values obtained in the present work are in excellent agreement with analogous values previously estimated from oxygen equilibrium measurements.