Figure 5.

MBP-Rcp1 is a substrate for AsphyA-ST kinase activity. (A) Autoradiograph and Coomassie blue-stained blot of Pr and Pfr forms of AsphyA-ST (PCB adduct; 1 μg) incubated alone or with MBP-Rcp1 (1 μg) under standard kinase assay conditions (see Materials and Methods). As controls, a mixture of purified MBP (1.5 μg) and the Pfr form of AsphyA-ST (PCB adduct; 1 μg), purified MBP-RCP1 (1 μg) or purified MBP (1.5 μg) incubated under standard kinase assay conditions (see Materials and Methods) are shown in the right three lanes. (B) Acid and base hydrolytic stability of the mixture of AsphyA-ST (PCB adduct, 1 μg) and MBP-Rcp1 (1 μg) was determined as described in Fig. 1.