ROGER GREEN,MEDICINE,ST.JOHN'S,NF,CAN (roger at kean.ucs.mun.ca) wrote:
: Well, here's a real beehive of activity!!
: Lets see if anybody is out there.
: I am trying to discover what is the approximate molar ratio of NAD to NADH
: in the CYTOPLASM of a resting (aerobic) animal cell ( a muscle cell if
: possible). Can't seem to find the information readily available.
:: Roger C. Green, Faculty of Medicine Phone: (709)737-6884
: Memorial University , St. John's, Newfoundland FAX : (709)737-7010
I'd like to know likewise in cardiac myocytes. I would guess
that NADH/NAD would be in equilibrium with mitochondrial NADH/NAD
because of the malate-aspartate shuttle (I hope that I have the correct
shuttle system). I saw a paper from a few years back by Balaban
(Biophysical Journal?) measuring mitochondrial NADH/NAD ratio (no molar
values) as 0.44. They used the fluorescence property of NADH.
Interestingly, they saw no impact on fluorescence from increasing
lactate concentration, which presumably would decrease cytosolic NADH
via the lactate dehydrogenase reaction. Anyways, I know of no
literature measuring actual molar values, the NADH/NAD is an indicator
of redox state and has been tracked by those interested in the control
of oxidative phosphorylation. Maybe, one of the authors of those papers
(if you find them) could help you.
Richard Kondo
kondo at buphy.bu.edu
Cellular Biophysics
Boston University, Boston Massachusetts
