The members of this family lack the conserved catalytic lysine in subdomain II of kinase domain that is crucial for binding to ATP.

• 该激酶家族成员在通常保守的位于激酶区域第二亚区的赖氨酸位点，赖氨酸被半胱氨酸所替代，但激酶的生物活性没有发生变化。