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.

ERK2 S503-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.

ERK2 S503-p
Regulatory protein:
ERK2 R309-me
EGF S115-p
EPZ015666 R309-me
ischemia S515-p
LY3214996 S503-p
MLN8054 S515-p
nocodazole T505-p
seliciclib S503-p
siRNA R309-me , S503-p
U0126 S115-p