Sandbox Reserved 774: Difference between revisions
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==Chemical Mechanism== | ==Chemical Mechanism== | ||
After the formation of a ternary complex of acetyl-CoA, histone and enzyme, an active site base deprotonates lysin, which allows for direct attack of the N-e-lysine on the carbonyl carbon of acetyl-CoA. Additionally, without a histone acceptor, slow rates of enzyme auto-acetylation (7 x 10-4 s-1, or ~2500-fold slower than histone acetylation; kcat = 1.6 s-1) and of CoA formation (0.0021 s-1) were not consistent with a kinetically competent acetyl-enzyme intermediate. | Post-translational modification of histones is linked to numerous cellular processes. These include transcriptional regulation, DNA damage repair, and DNA replication. One common histone modification, N-e-lysine acetylation, is controlled by the opposing actions of histone acetyltransferases (HATs) and deacetylases (HDACs). After the formation of a ternary complex of acetyl-CoA, histone and enzyme, an active site base deprotonates lysin, which allows for direct attack of the N-e-lysine on the carbonyl carbon of acetyl-CoA. Additionally, without a histone acceptor, slow rates of enzyme auto-acetylation (7 x 10-4 s-1, or ~2500-fold slower than histone acetylation; kcat = 1.6 s-1) and of CoA formation (0.0021 s-1) were not consistent with a kinetically competent acetyl-enzyme intermediate. | ||
