This was supported by the loss in activity of the soluble enzyme when treated with GSH; Fig. S4.† Next, we examined the cytotoxicity of SNP–DSP–ASNase–AT on cancer cells for which the sensitivity to ASNase activity is established, namely hepatocellular carcinoma HepG2 cells.35,36 The cytotoxic effect of SNP–DSP–ASNase–AT was compared to the effect of SNPs and SNP–Glu–ASNase–OS. The gene discussed is DSP; the disease is hepatocellular carcinoma.