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 S151-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.

CK2A1 S24-p
ERK2 S151-p
DRB S151-p
ephrin_B1 Y143-p
GF109203X S151-p
H-89 S151-p
PD98059 S151-p
SB203580 S151-p