NAD⁺/NADH (Reducing-Power Oscillation)
NAD⁺/NADH is the τ-categorical reducing-power oscillator: a two-state cycle that carries hydride pairs (2e⁻ + H⁺) from catabolic dehydrogenations to the electron transport chain. It is the τ-categorical complement to ATP/ADP — where ATP/ADP currency-circulates phosphoryl-transfer free energy, NAD⁺/NADH currency-circulates redox free energy. Together they span the two independent free-energy axes of cellular metabolism.
τ-Definition
NAD⁺/NADH is the τ-categorical reducing-power oscillator: a two-state cycle that carries hydride pairs (2e⁻ + H⁺) from catabolic dehydrogenations to the electron transport chain. It is the τ-categorical complement to ATP/ADP — where ATP/ADP currency-circulates phosphoryl-transfer free energy, NAD⁺/NADH currency-circulates redox free energy. Together they span the two independent free-energy axes of cellular metabolism.
Categorical invariant. Two-state τ-categorical oscillation: NAD⁺ + 2e⁻ + H⁺ ⇌ NADH; standard reduction potential E°' ≈ -320 mV; couples ~110 dehydrogenase reactions to the ~10-pump ETC.
Primary registry anchor:
VI.D32
τ-Derivation Chain
-
I.K0— Universe Postulate -
VI.D15— Life Sector -
VI.D31— Metabolic Circulation -
VI.T09— Metabolism = Life Loop Class -
VI.P11— Krebs Cycle as Loop_L instantiation — NAD⁺/NADH cycle threads through the cycle -
VI.D32— ATP/ADP Oscillation — NAD⁺/NADH is the second canonical currency cycle, coupled via OXPHOS
Empirical Correlate
Biomarker: Cytosolic [NAD⁺] ≈ 0.3-0.5 mM with NAD⁺/NADH ratio ≈ 700:1 (cytosol) and ≈ 7:1 (mitochondrial matrix); NADP⁺/NADPH ratio ≈ 1:100 (anabolic); standard reduction potential E°'(NAD⁺/NADH) = -320 mV.
Measurable range: Per-cell NAD⁺ pool ~10⁸ molecules; whole-body NAD⁺ flux ~9 g/day; NAD⁺ depletion (e.g., in CD38 hyperactivity, sirtuin overload) drops cytosolic levels 30-70% with strong metabolic phenotype; intrinsic NADH fluorescence (340 nm ex / 460 nm em) is the basis of optical metabolic imaging.
Observation method: Enzymatic cycling assay (Trinity / Promega NAD/NADH-Glo), LC-MS of nucleotide pool, intrinsic NAD(P)H autofluorescence (FLIM, two-photon), genetically encoded biosensors (SoNar, RexYFP), HPLC of acid extracts.
Calibration anchor: LG-Y02-kinetic-pseudoscalar-channel
Anchor chain:
- VI.L18 chirality channel
- D-ribose handedness in NAD⁺ adenine and nicotinamide ribose
- stereospecific hydride transfer (A-side vs B-side dehydrogenases) preserved across all life
Manuscript reference: manuscript-sources/book-06/part03/ch19-metabolism.tex
Lean Coverage
Status: Planned