Oxygen capacity （P50，Hill coefficient, Bohr,Chloride and CO2 effects）. It would be most useful to determine the entire curve of bound oxygen as funtion of PO2. The most common of equipment is Hemox-analyzer (TCS scientific corp.)

Why can't you go with potential measurement. Do cyclic voltametric study. As if Hb is redox protein, so we can measure the current and potential very nicely with prominent redox peak. I think this will work.

Good luck

Thank you Rajesh for your response. Redox potential or optical density whatever I measure, I need to vary the partial pressure of oxygen. So, the problem remains. However, I've found something on the internet, an instrument called oxygraph that supposedly can do the job.

Is isothermal calorimetry an option? Or speak to someone who can do resonance raman or EPR of heme proteins? Probably the last two would be overkill. You might alos be able to do something by looking at visible spectra of the heme (Soret peaks and then peak above 500 nm should change). The shape and chirality of the heme should change upon binding and oxidation changes, therefore circular dichroism can also be used. Mixtures of disolved oxygen can be created by mixing a saturated (shaken) solution with a completely deoxygenated solution. Deoxygenated solutions can be created by sparging with argon. You may also be able to achieve it by autoclaving the water or buffer and then moving the solution immediately to an anoxic environment. An oxygen electrode can then be used to ensure that the deoxygenated solutions is in fact free of oxygen. You can add dithionite to a saturated soluition in order to measure the signal of a fully oxygenated solution (before adding dithionite) and an anoxic solution (after adding dithionite). You will need this to prove exactly what your oxygen concentration is in each sample and will need to do this before each reading.

Oxygen capacity （P50，Hill coefficient, Bohr,Chloride and CO2 effects）. It would be most useful to determine the entire curve of bound oxygen as funtion of PO2. The most common of equipment is Hemox-analyzer (TCS scientific corp.)