Expanding on our offerings of long wavelength, highly sensitive SIRT assays, AnaSpec, Eurogentec Group, is pleased to release 2 assay kits for SIRT2, the SensoLyte^® 520 FRET SIRT2 Assay Kit and the SensoLyte^® Green SIRT2 Assay Kit. The substrate found in the SensoLyte^® 520 FRET SIRT2 Assay Kit employs a FRET substrate, and the peptide sequence is derived from a human alpha-tubulin sequence surrounding the deacetylation site of SIRT2. The SensoLyte^® Green SIRT2 Assay Kit provides a fluorogenic substrate with a human p53 derived sequence. Compared to lower emitting substrates found in existing commercial kits, these kits employ fluorimetric substrates that emit in the green range of 520 nm. At this higher wavelength, the contribution of autofluorescence is minimal.

These kits provide a convenient, two-step homogeneous procedure for measuring sirtuin 2 activity and for screening enzyme inhibitors and activators. In the first step, an acetylated substrate is incubated with sirtuin-containing samples. In the second step, deacetylated substrate is cleaved by the sirtuin developer, resulting in an increase of fluorescence that can be detected with excitation at 490 nm and emission at 520 nm. Fluorescence produced is proportional to SIRT2 activity.

Figure 1. Inhibition of SIRT2 activity by Ro-31-8220 as measured with SensoLyte^® 520 FRET SIRT2 Assay Kit (Cat# 72189).

Figure 2. Sensitivity of the SensoLyte^® 520 FRET SIRT2 Assay Kit(Cat# 72189).

Histone deacetylases (HDACs) act as transcriptional repressors of genes catalyzing the removal of acetyl groups from a ε-N-acetyl lysine of histone.¹ Sirtuins comprise a unique class of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases (class III HDACs) that target multiple protein substrates to execute diverse biological functions. Sirtuins catalyze a reaction that couples lysine deacetylation to NAD hydrolysis, yielding O-acetyl-ADP-ribose and nicotinamide.²

Sirtuin 2 (SIRT2) belongs to the family of Sir2 (Silent Information Regulator 2) proteins. Substrates for SIRT2 are not limited to histones, but also include various transcription factors such as forkhead box (FOXO) transcription factors (FOXO1, FOXO3a) that modulate metabolic, cell cycle and cell death related pathways.^{3, 4} Other prominent substrates include the tumor suppressor p53 and alpha-tubulin.^{5, 6} Human SIRT2 is a cytoplasmic protein that increases in abundance during mitosis and regulates major events of cytokinesis.⁷

Recombinant human SIRT2, a positive control included in the kits, is also available as a separate item.

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3. Wang, F. et al. Aging Cell 6, 505 (2007).
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5. Jin, Y.-H. et al. Biochem. Biophys. Res. Commun. 368, 690 (2008).
6. Inoue, T. et al. Cell Cycle 6(9) (2007) .
7. Dryden, S. et al. Mol. Cell. Biol. 23, 3173 (2003).