Re: [HAPS-L] NADH Shuttle Mechanism.

[Ken Saladin <ksaladin@xxxxxxxxxx>]

At 04:14 PM 1/10/2006, you wrote:


Hello All.

I'm trying to find some information on the specific types of cells
that use a shuttle mechanism to move NADH into the mitochondria. Also,
if anyone has any suggestions about where to get some more specifics
on this process of why we get 36-38 ATP I would appreciate it.

Thanks! Hope everyone has a great semester!

Darren Mattone



I thought I might find something on the NADH transport in Alberts et al., Molecular Biology of the Cell, but I came up empty-handed. While I do not remember my source, back when I was looking into this to write the first edition of my textbook, I found information that mitochondria cannot import NADH from the cytosol. The NADH generated by glycolysis does not (to my knowledge) enter them. Below is an excerpt from what I wrote for the A&P-level student reader (and what has so far survived a decade of peer review without adverse comment). This may be more superficial than what you're looking for, but perhaps will be of a little help. Thank you for asking, Darren. If anyone else has information to contradict this, then I need to make another textbook correction!

     Furthermore, the NADH generated by glycolysis cannot enter the mitochondria and donate its electrons directly to the electron-transport chain. In liver, kidney, and myocardial cells, NADH passes its electrons to malate, a “shuttle” molecule that delivers the electrons to the beginning of the electron-transport chain. In this case, each NADH yields enough energy to generate 3 ATP. In skeletal muscle and brain cells, however, the glycolytic NADH transfers its electrons to glycerol phosphate, a different shuttle that donates the electrons farther down the electron-transport chain and results in the production of only 2 ATP. Therefore the amount of ATP produced per NADH differs from one cell type to another and is still unknown for others.

Ken Saladin