Recombinant GST fusion protein fused to full length human SAPK4, expressed in E. coli. Human stress-activated protein kinase-4 (SAPK4) is a novel MAP Kinase family member whose amino acid sequence is 60% identical to that of the other three SAP Kinases which contain a TGY motif in their activation domain. Recent results suggest that cellular functions attributed to SAPK1 and/or SAPK2 may be mediated by either SAPK3 or SAPK4. Specific Activity: ~100U/mg Unit Definition: 1unit pf p38 delta/SAPK4 activity is defined as 1nmol phosphate incorporated into 0.33mg/ml myelin basic protein/minute at 30C with a final ATP of 100uM. Kinase Assay: Enzyme was tested in a functional kinase assay by using 10-100ng of active SAPK4 to phosphorylate MBP in vitro. Storage and Stability: May be stored at 4C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20C. Aliquots are stable for 6 months after receipt at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.