It's a little early to tell whether this will actually shed any light upon the metabolic processes of human longevity, even though Sir2 is involved, but it is interesting nonetheless: "making glucose is highly influenced by a large enzyme complex already known to fix damaged DNA, and which apparently affects yeast life span through a common chemical process - acetylation. ... when continuously acetylated, the so-called NuA4 enzyme complex causes yeast cells to live longer than they would under normal conditions. ... the constantly acetylated form of yeast cell can outlive the unaltered cell by 20 percent and that the constantly de-acetylated form had an 80 percent reduction in its lifespan compared to the unaltered cell. ... Because the NuA4 complex is highly conserved among species, what we've found in yeast translates to humans as well. What we've revealed about longevity in yeast perhaps someday can translate to human health. ... the team provided the first evidence that acetylation controls the activity of an enzyme called Pck1p, critical to sugar production in yeast and probably human cells. This enzyme is also controlled by the enzyme Sir2, which removes the acetyl group. Sir2 is heavily implicated in aging and a number of diseases by recent studies in mammals."