Characterizing Sirtuin 3 Deacetylase Affinity for Aldehyde Dehydrogenase 2

Mitochondrial
aldehyde dehydrogenase (ALDH2) plays a central role
in the detoxification of reactive aldehydes generated through endogenous
and exogenous sources. The biochemical regulation of enzyme activity
through post-translational modification provides an intricate response
system regulating mitochondrial detoxification pathways. ALDH2 is
a known target of lysine acetylation, which arises as a consequence
of mitochondrial bioenergetic flux and sirtuin deacetylase activity.
The mitochondrial deacetylase Sirtuin 3 (SIRT3) has been reported
to alter ALDH2 lysine acetylation status, yet the mechanism and consequence
of this interaction remain unknown. The in vitro results presented
here provide a novel biochemical approach using stable-isotope dilution
mass spectrometry to elucidate which lysine residues are targeted
by SIRT3 for deacetylation. Furthermore, HPLC–MS/MS and computational
modeling elucidate a potential role for acetyl-Lys369 on ALDH2 in
perturbing normal β-nicotinamide adenine dinucleotide (NAD+) cofactor binding.