Substrate specificity of SIRT1-catalyzed lysine Nε-deacetylation reaction probed with the side chain modified Nε-acetyl-lysine analogs

Peptides containing L-N-epsilon-acetyl-lysine (L-AcK) or its side chain modified analogs were prepared and assayed using SIRT1, the prototypical human silent information regulator 2 (Sir2) enzyme. While previous studies showed that the side chain acetyl group of L-AcK can be extended to bulkier acyl groups for Sir2 (including SIRT1)-catalyzed lysine N-epsilon-deacylation reaction, our current study suggested that SIRT1-catalyzed deacetylation reaction had a very stringent requirement for the distance between the alpha-carbon and the side chain acetamido group, with that found in L-AcK being optimal. Moreover, our current study showed that SIRT1 catalyzed the stereospecific deacetylation of L-AcK versus its D-isomer. The results from our current study shall constitute another piece of important information to be considered when designing inhibitors for SIRT1 and Sir2 enzymes in general. (C) 2009 Elsevier Inc. All rights reserved.