NAD+-dependent deacetylases are enzymes that remove acetyl groups from proteins, a process known as deacetylation. They require NAD+ (nicotinamide adenine dinucleotide) as a cofactor to function. This modification can influence various cellular processes, including gene expression, metabolism, and aging. These enzymes are part of the sirtuin family, which plays a crucial role in regulating cellular health and longevity. By modulating protein activity and stability, NAD+-dependent deacetylases help maintain cellular homeostasis and respond to environmental changes, making them important for overall biological function.