The following questions are based on data, graphs, and figures from the following article: Naphthoquinone-mediated Inhibition of Lysine Acetyltransferase KAT3B/p300, Basis for Non-toxic Inhibitor Synthesis. Mohankrishna Dalvoy Vasudevarao et al. The Journal of Biological Chemistry, 289, 7702-7717. March 14, 2014 . doi: 10.1074/jbc.M113.486522
Fig 2AB. To simplify study of these effects, the investigators performed in vitro (cell free) assays in which no ROS (superoxide, hydrogen peroxide) would be produced. They studied two different KATs, p300 (A) and CBP (B) using HeLa cell core histones, with 100 μm plumbagin (lanes 5–7 in A and B) either in the presence or absence of NAC, DTT, and another reducing agent Trolox (lane 8). Interpret the results. What part of NAC and DTT appear important in their effects on plumbagin inhibition.
Lanes 5 and 7 and Lane 5 and 8 show that both NAC and DTT (both of which have thiols) relieve the inhibitory effect of blumbagin on KAT activity. Lanes 5 and 8 show that Trolox, which does not have a thiol group, does not relieve blumbagin inhibition.
