Chk1 Protein, Human (sf9, GST)

The serine/threonine protein kinase CHK1 is essential for checkpoint-mediated cell cycle arrest and DNA repair. It may negatively regulate cell cycle progression and maintain genomic integrity during the normal cell cycle. The kinase recognizes the consensus sequence [R-X-X-S/T] and phosphorylates CDC25A, CDC25B, and CDC25C. Phosphorylation of CDC25A inhibits its activity and promotes proteolysis, while increasing tyrosine phosphorylation of CDK-cyclin complexes. In addition, the kinase phosphorylates RAD51 and TP53, enhancing DNA repair and cell cycle arrest. Chk1 Protein, Human (sf9, GST) is the recombinant human-derived Chk1 protein, expressed by Sf9 insect cells , with N-GST labeled tag. The total length of Chk1 Protein, Human (sf9, GST) is 476 a.a., with molecular weight of ~80 kDa.

The serine/threonine protein kinase CHK1 is essential for checkpoint-mediated cell cycle arrest and activation of DNA repair caused by DNA damage or unreplicated DNA. It may also negatively regulate cell cycle progression during the normal cell cycle, utilizing various mechanisms to maintain genomic integrity. The kinase recognizes the substrate consensus sequence [R-X-X-S/T] and phosphorylates CDC25A, CDC25B, and CDC25C.
Phosphorylation of CDC25A at specific residues creates binding sites for 14-3-3 proteins, inhibiting their activity, whereas additional phosphorylation promotes proteolysis of CDC25A. Inhibition of CDC25 results in increased tyrosine phosphorylation of CDK-cyclin complexes, arresting cell cycle progression. The kinase also phosphorylates RAD51 and TP53, enhancing DNA repair and promoting cell cycle arrest, respectively. In addition, it regulates chromatin assembly by phosphorylating TLK1 and may be involved in replication fork maintenance through PCNA regulation. It can also phosphorylate histone H3.1, leading to epigenetic repression of certain genes, and phosphorylate RB1 to promote its interaction with E2F transcription factors. In addition, it reduces replication stress and activates the G2/M checkpoint by regulating PABIR1/FAM122A and stabilizing WEE1 levels and activity.

The specific activity was determined to be > 15 nmol/min/mg using CHKtide peptide (KKKVSRSGLYRSPSMPENLNRPR) as substrate.

Human

Sf9 insect cells

N-GST

AAM78553.1 (M1-T476)

1111  [NCBI]

Approximately 80 kDa

Greater than 85% as determined by reducing SDS-PAGE

Solution.

Supplied as a 0.2 μm filtered solution of 20 mM Tris, 500 mM NaCl, pH 7.4, 10% glycerol, 2 mM GSH.

<1 EU/μg, determined by LAL method.

Please use rapid thawing with running water to thaw the protein.

Stored at -80°C for 1 year. It is stable at -20°C for 3 months after opening. It is recommended to freeze aliquots at -80°C for extended storage. Avoid repeated freeze-thaw cycles.

Shipping with dry ice.