LDH works to prevent muscular failure and fatigue in multiple ways. The lactate-forming reaction generates cytosolic NAD+, which feeds into the glyceraldehyde 3-phosphate dehydrogenase reaction to help maintain cytosolic redox potential and promote substrate flux through the second phase of glycolysis to promote ATP generation. This, in effect, provides more energy to contracting muscles under heavy workloads. The production and removal of lactate from the cell also ejects a proton consumed in the LDH reaction- the removal of excess protons produced in the wake of this fermentation reaction serves to act as a buffer system for muscle acidosis. Once proton accumulation exceeds the rate of uptake in lactate production and removal through the LDH symport,  muscular acidosis occurs.
The salvage pathways used in microorganisms differ from those of mammals .  Some pathogens, such as the yeast Candida glabrata and the bacterium Haemophilus influenzae are NAD + auxotrophs – they cannot synthesize NAD + – but possess salvage pathways and thus are dependent on external sources of NAD + or its precursors.   Even more surprising is the intracellular pathogen Chlamydia trachomatis , which lacks recognizable candidates for any genes involved in the biosynthesis or salvage of both NAD + and NADP + , and must acquire these coenzymes from its host . 
Reduced CoQ (CoQH 2 ) diffuses in the lipid phase of the membrane and donates its electrons to complex III, whose principal components are the heme proteins known as cytochromes b (encoded by the MT-CYB gene) and c1 (encoded by the CYC1 gene) and a non-heme-iron protein, known as the Rieske iron sulfur protein (encoded by the UQCRFS1 gene). Complex III is known as ubiquinol-cytochrome c oxidoreductase or as CoQ-cytochrome reductase and often as the cytochrome bc 1 complex. Complex III is composed of 11 protein subunits, all of which, excepting cytochrome b , are encoded by the nuclear genome. The MT-CYB, CYC1, and UQCRFS1 encoded proteins constitute the electron transfer center of complex III. In contrast to the heme of hemoglobin and myoglobin, the heme iron of all cytochromes participate in the cyclic redox reactions of electron transport, alternating between the oxidized (Fe 3+ ) and reduced (Fe 2+ ) forms. The electron carrier from complex III to complex IV is the smallest of the cytochromes, cytochrome c (molecular weight 12,000; encoded by the CYCS gene). The releaase of cytochrome c from the mitochoindria to the cytosol is the major trigger of the mitochondrially-induced apoptosis pathway .