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.

ERK1 S39-p , T381-p
ERK2 S39-p , T381-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.

ERK1 S39-p , T381-p
Regulatory protein:
EGFR S39-p , T381-p
PRKD1 S394-p
angiotensin_2 S394-p
CGP57380 S39-p , T381-p
dasatinib S2-p
gefitinib S39-p , T381-p
ischemia S39-p
MG132_withdrawal S39-p
nocodazole S39-p , S359-p
SCH772984 S39-p , T381-p
selumetinib S39-p
vemurafenib S39-p