Kinase, in vitro: 

An enzyme-substrate reaction that occurs in non-living experimental conditions such as a test tube. For example, a purified enzyme is reacted with a substrate protein or mixture of proteins or peptides.

Chk1 S743-p
 Putative in vivo kinases: 

An enzyme-substrate reaction that occurs within living cells; includes cultured cells, ex vivo samples, and intact organisms. In the case of kinases, the large number of protein kinases in intact cells makes exact identification of the responsible kinase challenging.

Chk1 S679-p , S743-p
Regulatory protein:
PRP4 S159-p
caffeine S743-p
ionizing_radiation S743-p
MG132_withdrawal S159-p
nocodazole S159-p
selumetinib S82-p
UCN-01 S743-p
vemurafenib S82-p