Two vials of 250 µl each are provided in loading buffer consisting of 50 mM Tris-HCl (pH 6.8), 5 mM EDTA, 10 mM DTT, 1% (w/v) SDS, 10% (w/v) glycerol. Store at -20°C. Avoid repeated freezing and thawing. Guaranteed stable for 1 year when properly stored.