DNA methyltransferase 1 (DNMT1) is an emerging target for the treatment of 
cancer, brain disorders, and other diseases. Currently, there are only a few 
DNMT1 inhibitors with potential application as therapeutic agents or research 
tools. 5,5-Methylenedisalicylic acid is a novel scaffold previously identified 
by virtual screening with detectable although weak inhibitory activity of DNMT1 
in biochemical assays. Herein, we report enzyme inhibition of a structurally 
related compound, trimethylaurintricarboxylic acid (NSC97317) that showed a low 
micromolar inhibition of DNMT1 (IC(50) = 4.79 μM). Docking studies of the new 
inhibitor with the catalytic domain of DNMT1 suggest that NSC97317 can bind into 
the catalytic site. Interactions with amino acid residues that participate in 
the mechanism of DNA methylation contribute to the binding recognition. In 
addition, NSC97317 had a good match with a structure-based pharmacophore model 
recently developed for inhibitors of DNMT1. Trimethylaurintricarboxylic acid can 
be a valuable biochemical tool to study DNMT1 inhibition in cancer and other 
diseases related to DNA methylation.