Figure 3
From: A novel mass spectrometry-based assay for GSK-3β activity
![Figure 3](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1471-2091-6-29/MediaObjects/12858_2005_Article_118_Fig3_HTML.jpg)
2B-Sp m/z ratio shifts in response to varying amounts of lithium chloride, and sodium chloride. GSK-3β specificity for the 2B-Sp target peptide was examined in a kinase assay with lithium chloride (LiCl, green bars, n = 3) a well-known inhibitor of GSK-3β, and sodium chloride (NaCl, purple bars, n = 3), a salt with no known GSK-3β inhibitory characteristics. Increasing amounts of LiCl (0–50 mM), or NaCl (0–50 mM) were added to kinase assays containing 125 ng of 2B-Sp peptide, and 6.25 ng of recombinant GSK-3β. M/z ratios were subsequently analyzed using SELDI-TOF-MS. Pooled data for LiCl assays are represented as mean +/- SEM values. NaCl assays are represented as mean values.