Fig. 2.

Effects of enzymatic oxidation of DA and DOPAL with tyrosinase on AS quinonization and oligomerization. DA or DOPAL (30 μM each) was incubated with tyrosinase (+Tyr) or without tyrosinase (no Tyr) for 20 minutes at room temperature and then incubated with AS (3 μM) for 1 hour at 37°C. (A and B) Concentration course of DA or DOPAL (10, 30, and 100 μM each) oxidation with Tyr. (A and C) Quinonized AS was detected by nIRF spectroscopy (red). (B and D) Oligomerized AS was detected by western blotting (green). N = number of replicates; 1 = DA; 2 = DOPAL. Enzymatic oxidization augmented DOPAL-induced oligomerization and quinonization of AS. Incubation of AS with DA and Tyr resulted in a smear of high molecular weight AS. DA did not quinonize AS even in the setting of enzymatic oxidation by Tyr.