Leupeptin hemisulfate salt
Product Number: E03740
CAS Number: 103476-89-7
Storage Temperature: –20°C
Product Description:
Appearance: White amorphous powder
Molecular Formula: C20H38N6O4.1/2H2SO4.H2O
Molecular Weight: 493.62
Leupeptin is a reversible competitive inhibitor of serine and thiol proteases. It has been reported to inhibit calpain, cathepsin B, cathepsins H and L, and trypsin. A typical working concentration is in the range of 10-100mM. Leupeptin appears to be equally effective in any salt form, adjusting for equivalent peptide content. The hemisulfate salts were the first to be commercially available. Microbially produced leupeptin inhibitor was first isolated as a mixture of two very similar forms: acetyl-Leu-Leu-Arg-al and propionyl-Leu-Leu-Arg-al. Although the propionyl leupeptin is active as an inhibitor, the acetyl form is more commonly used and is available from Sigma in several salt different forms.
Preparation Instructions:
Salts of leupeptin are reported to be soluble in water, ethanol, acetic acid, and DMF. Leupeptin hemisulfate is soluble in water (50mg/ml), yielding a clear solution.
Storage/Stability:
When stored properly, dessicated at –20°C, the lyophilized powder should be stable for at least 2 years.
A 10mM aqueous solution is stable for a week at 4 °C and at least 6 months frozen in aliquots at –20°C. At working concentrations (10-100mM) a solution is stable for only a few hours; the stock solution should be stored on ice for intermitted use over several hours.
The primary mechanism of inactivation of leupeptin activity is racemization of the L-arginal; the D-arginal form is totally inactive. If the aldehyde is oxidized, but retains its L-configuration, the resulting compound does have some inhibitory activity.
Precautions and Disclaimer:
For Laboratory Use Only. Not for drug, household or other uses.