GST-cJun in 25mM Tris (pH7.4) containing 0.5mM EDTA, 50mM NaCl, 1mM DTT, 10% glycerol at 1.0mg/ml
10X Kinase Buffer: 1.0ml of 250mM HEPES buffer (pH7.4) containing 100mM MgOAc, 0.5mM ATP, 10mM DTT.

Shipped frozen on dry ice. Upon receiving, store the product at -80^oC until use. If not all the content is to be used, aliquot the original vial and refreeze at 80^oC after the initial thaw. Working aliquot can be stored at 2-8^oC for no more than 2 weeks. Avoid repeated freezing and thawing.

GST-cJun (1-79) serves as a highly specific substrate for c-Jun N-terminal kinases (JNK) due to the presence of a JNK docking region. It's not phosphorylated by ERKs and p38 MAPKs. Therefore, it's a preferred substrate for in vitro JNK activity assays. Standard reaction conditions are performed by incubating the following mixture with various amounts of JNK at 30^oC for 30 min in a total volume of 40 ul, followed by SDS-PAGE analysis. A standard reaction mixture contains: 5ul of 10X Kinase Buffer provided, 2uCi [P³²]-ATP, 2ug of GST-cJun protein and various amounts of JNK (e.g. 0.1ug of recombinant JNK, cell lysates or immunoprecipitates.