Figure 2.

The CDK9 Tail Is Required for the Ordered Substrate Addition Catalytic Mechanism

(A) Theoretical model curves for mixed and competitive inhibition assuming the same K_M, K_i, and V_max in both cases.

(B) Activity of CDK9_FL/cyclin T in the absence and presence of 2.5 μM ADP, in the presence of 100 μM ATP and increasing amounts of CTD.

(C) Activity of CDK9_FL/cyclin T in the absence and presence of 2.5 μM ADP, in the presence of 36 μM CTD and increasing amounts of ATP.

(D) Activity of CDK9₃₃₀/cyclin T in the absence and presence of 2.5 μM ADP, in the presence of 100 μM ATP and increasing amounts of CTD. All measurements were done in triplicate and reproduced in independent experiments.

Error bars in (B)–(D) represent SEs. See also Figure S3.