Deacetylase is any enzyme that removes acetyl groups from other proteins.
Histone deacetylase (HDAC) is an enzyme responsible for the effects elicited by the broad spectrum deacetylase inhibitors. HDAC1 is also required for active transcription of certain proteins. This enzyme is specifically acetylated during the phase of transcriptional decline. The acetylation of HDAC1 is done by the acetyltransferase p300. So, HDAC1 has a key role in transcription, which shows that the regulation of acetyltransferases and deacetylases influence gene expression. Understanding the HDAC function and how these enzymes are regulated by cellular signaling pathways has various clinical implications and is critical for researchers to use these inhibitors to create more efficient drugs. Additionally, HIDAC regulate the transcription of proteins involved in cancerous cells. By removal of acetyl groups from histones, HDACs create a non-permissive chromatin conformation that prevents the transcription of genes that encode proteins involved in tumorigenesis. In addition to histones, HDACs bind to and deacetylate a variety of other protein targets including transcription factors and other abundant cellular proteins implicated in control of cell growth, differentiation and apoptosis
The activity of SIRT1 is regulated by its phosphorylation status. This enzyme is directly phosphorylated by cyclin B-CDK1 complex. This complex is the first evidence of a kinase targeting SIRT1. Through this, the relevance of SIRT1 phosphorylation will be necessary for grasping how SIRT1 phosphorylation will regulate deacetylase activity.
Mellert, Hestia S. and McMahon, Steven B. "Biochemical pathways that regulate acetyltransferase and deacetylase activity in mammalian cells." Trends in Biochemical Sciences Vol. 34 No. 11. 2009.