Uniblue A sodium serves as a reactive protein stain for covalent pre-gel staining (Ex=594 nM) [1].

Uniblue A: Prepare the derivatization buffer with 100 mM NaHCO3, 10% SDS, pH 8-9. Add 10 μL of 200 mM Uniblue A solution (dissolved in derivatization buffer) to 90 μL protein solution. Heat samples at 100°C for 1 minute for staining. Add 100 μL of reducing solution (10% glycerol, 20 mM dithiothreitol [DTT], in 200 mM Tris buffer, pH 6.8). Excess Uniblue A reacts with Tris, forming a blue compound as a running front indicator in electrophoresis. Heat the sample another minute at 100°C for efficient reduction, then cool to room temperature. Add 20 μL of 550 mM iodoacetamide (IAA) alkylation solution and incubate for 5 minutes. Subject samples to SDS-PAGE. Note: Dry protein samples or samples in compatible buffers (free of amines) can be diluted directly with the derivatization buffer solution to 5 mg/mL. In other cases, trichloroacetic acid (TCA)/acetone precipitation or buffer exchange by ultrafiltration is recommended. As a positive control, use bovine serum albumin (BSA) in derivatization buffer at 10 mg/mL.