MLS0315771 is an effective and biologically active competitive phosphomannose isomerase (MPI) inhibitor (IC50: ~1 μM and a Ki: 1.4 μM).
MLS0315771 is toxic to the zebrafish embryos above 2 μM. MLS0315771 toxicity at higher concentrations is an off-target effect. MLS0315771 enhances mannose flux toward glycosylation. It ~50% of embryos appeared sick within 20 min at 8-10 μM, and most of them die by 30-60 min.