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Re: [HAPS-L] NADH Shuttle Mechanism.



Most of the biochem books are now giving 30-32 ATP/glucose as the average yield. A good discussion of why this is can be found in the Horton Biochemistry (Prentice Hall).
Dee



At 02:33 PM 1/12/2006 -0500, you wrote:
Thanks, Bob. Very helpful. Could you point to the reference by your
competitor? I'd like to read the article.

Darren Mattone
Department of Life Science
Muskegon Community College
Muskegon, Mi

On 1/12/06, Bob Tallitsch <bitallitsch@xxxxxxxxxxxxx> wrote:
>
> Darren:
>
>
> I'm not sure I fully understand both questions, but here is my attempt.....
>
> Most of the energetically relevant NADH is actually produced within the
> mitochondria by the citric acid cycle.  NADH movement into mitochondria is
> generally thought to occur as a result of the malate-aspartate shuttle
> system: Oxaloacetate in the cytosol is reduced to malate by NADH. The malate
> enters the mitochondria via the malate transporter.  Then, within the
> mitochondria malate reduces NAD+ to NADH and becomes oxaoloacetate.  The
> oxaloacetate is recycled back to the cytosol via aspartate. This results in
> a net movement of NADH "reducing equivalents" from the cytosol to the
> mitochondiral matrix. So, the real question is "how does NAD+ get into the
> mitochondria"? I checked the database.....a by one of my competitors (!) is
> one of the few straightforward studies on the subject. I pasted in the
> abstract at the end of this message.
>
> As to the number of ATPs formed per glucose....the theoretical yield is 38
> ATPs.  However,  ATP is synthesized as a result of the H+ gradiaent
> generated by the electron transport chain.  So, any other mechanism that
> allows H+ movement across the membrane (without ATP synthesis) can decrease
> the efficiency.  One specific example is the H+/phosphate transporter; this
> is necessary to import inorganic phosphate needed to convert ADP to ATP
> within the mitochondria.  So, in reality the 38 ATP per glucose is rarely
> attained.
>
> I hope this helps!
>
>
> Bob Tallitsch
>
>
>
> 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
>  Department of Biology
>  Muskegon Community College
>  Muskegon,Mi
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