Leupeptin

Leupeptin

Leupeptin, also known as "N"-acetyl-L-leucyl-L-leucyl-L-argininal, is a protease inhibitor that also acts as an inhibitor of calpain.

It is often used during "in vitro" experiments when a specific enzymatic reaction is being studied. When cells are lysed for these studies, proteases, many of which are contained within lysosomes, are released. These proteases, if freely present in the lysate, would destroy any products from the reaction being studied, and make the experiment uninterpretable. For example, leupeptin could be used in a calpain extraction to keep calpain from being hydrolyzed by specific proteases. The suggested concentration is 1-10 µM (0.5-1 µg/ml).

Leupeptin is an organic compound produced by actinomycetes, serine and cysteine proteases reversibly. Leupeptin inhibits serine proteinases (trypsin (Ki=13 µM), plasmin, porcine kallikrein) and cysteine proteinases (papain, cathepsin B, endoproteinase Lys-C). It does not inhibit chymotrypsin or thrombin. Leupeptin is a competitive and its inhbition may be relieved by an excess of substrate.

Leupeptin is soluble in water (stable for 1 week at 4ºC and 1 month at -20ºC), ethanol, acetic acid and DMF (Stock solution: 10 mM)

MW: leupeptin: 426.6; leupeptin hemisulphate monohydrate: 542.7.


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