Re: how is O2 transported to Complex IV active site?

Evgenij Barsukov wrote:
Basically subj.

It looks like traditional explanation of oxygen reduction assumes
that new O2 will get between Cu_b and a3 immediately after OH- is
removed.
But where will this oxygen come from? What is the oxygen transport
mechanism to the site? Is it a plain diffusion, or there is some
preferential pathway?

Regards,
Yevgen

Probably to make it a little more specific, it is clear how oxygen
is getting from air -->hemoglobin --> close to cells.
It is also clear that if CO2 level increases, there will be "oxygen
dumping" according to Bohr.
But is that all? It appears to be a very inefficient way to transport
O2 - dropping it into water right close to the place where it is actually needed but not quite there.
Now it needs to diffuse through 3 membranes - first through the cell membrane, then through external and internal mithohondrial membranes...
Somehow this does not add up as an essential and high-speed process.

Regards,
Yevgen
.