Figure 3.

SDS-PAGE analysis of RNase A modified by HOCl-serine. RNase A (10 mg/mL) was incubated with the HOCl-serine system in buffer A, as indicated in the legend to Figure 1, for 24 hours at 37°C. RNase A (20 μg of protein) was then subjected to electrophoresis on a 10–20% gradient polyacrylamide gel under denaturing (0.1% SDS) and reducing (1% β-mercaptoethanol) conditions. Reaction conditions were as follows: lane 1, RNase A alone; lane 2, RNase A + 5 mM L-serine + 4.5 mM HOCl; lane 3, RNase A + 10 mM L-serine + 9 mM HOCl; lane 4, RNase A + 5 mM glycolaldehyde; lane 5, RNase A + 10 mM glycolaldehyde; lane 6, RNase A + 10 mM L-serine; lane 7, RNase A + 9 mM HOCl; lane 8, RNase A + 10 mM L-serine + 9 mM HOCl + 20 mM NaCNBH₃. NaCNBH₃ was present during the incubation of HOCl and L-serine (lane 8).