Cell surface oxygen consumption

How does cell surface oxygen consumption occur? Here is the primary response in general (it's presumably not so basic!):

4e-+ 4H+ + O2 – > 2H2O

According to a study, specific amount of hydrogen peroxide is additionally produced and only a little superoxide (most likely for cell-cell signaling). Other electron acceptors can stand in for, or compete with oxygen as the terminal electron acceptor. The reaction occurs on the outer surface of the plasma membrane.

The wellspring of the electrons is cytoplasmic NADH, which is oxidized to NAD+ and H+ on the internal surface of the plasma layer. Every one of the electrons is transported by means of a plasma layer ubiquinone:semi ubiquinone cycle which at that point gives them to the redox protein on the outer cell surface.

Although I doubt that there is very much NADH or NAD+ in normal extra cellular fluid there has to be an NADH docking site on the outer redox enzyme as one of the hallmarks of cell surface oxygen consumption is that it can be halted completely by flooding the cell culture medium with NADH. Electrons from this then follow the dashed line to fully reduce the ubiquinone to ubiquinol and the system grinds to a halt.

In spite of the fact that I question that there is particularly NADH or NAD+ in typical additional cell liquid there must be a NADH docking site on the external redox compound as one of the signs of cell surface oxygen utilization is that it very well may be stopped totally by flooding the cell culture medium with NADH. Electrons from this at that point pursue the dashed line to completely lessen the ubiquinone to ubiquinol and the framework comes to a standstill.

So you can quantify cell surface oxygen consumption by the fall in utilization which happens when you include exogenous NADH similarly as you can gauge mitochondrial oxygen use by the fall in consumption, which happens when you include myxothiazol.

For what reason is the system there?

We should return to the two courses of glycolysis. Without the glycerophosphate transport (insulin flagging driven/driving) we have:

Glucose – > lactate – > mitochondria – > pyruvate – > TCA

Also, there is no consumption of cytoplasmic NAD+ as one is expended and one created in the glucose – > lactate process. With insulin signaling we have two parallel procedures:

Glucose – > glycerophosphate transport – > CoQ – > ETC

which devours cytoplasmic NADH, leaving none to change over pyruvate to lactate. So in parallel we need to prematurely end glycolysis at pyruvate:

Glucose – > pyruvate – > mitochondria – > TCA

which adjusts the cytoplasmic NADH:NAD+ proportion pleasantly.

Presently, we should consider a cell experiencing quick development so as to partition. For now I will overlook mitochondrial biosynthesis and think about what occurs if cytoplasmic pyruvate is devoured for amino acid biosynthesis. For every atom of pyruvate which has been redirected to an amino acid, there will be one less accessible to give cytoplasmic NAD+ by change to lactate, which will constrain glycolysis on the grounds that cytoplasmic NAD+ is basic for the oxidation of glyceraldehyde-3-phosphate.

Under these conditions cell surface oxygen consumption gives off an impression of being ready to venture in to oxidize cytoplasmic NADH to cytoplasmic NAD+, which at that point permits glycolysis and its related ATP generation. This appears to be especially significant if there is any kind of an issue with the ETC and the glycerophosphate transport.

Reference:

http://high-fat-nutrition.blogspot.com/2019/01/cell-surface-oxygen-consumption-2.html?m=1