The effect of temperature on the equilibrium and kinetic properties of a root effect haemoglobin from the marlin Tetrapturus audax.

The ligand binding properties of the Root effect haemoglobin of the marlin have been investigated in the temperature range 12-35 degrees C. An essentially symmetric displacement of the binding isotherms to higher concentration is observed on raising the temperature. Thermodynamic parameters have been obtained for the equilibrium binding constants, in terms of the two state model for co-operativity. Kinetic measurements indicate chain heterogeneity in both the T and R states. Activation parameters have been obtained for both chains in both quaternary states.