Anion exchange chromatography was frequently used to isolate negatively-charged bioactive peptides, such as GNPWM, an anti-ACE peptide [31], EIAQDFKTDL, an anti-obesity peptide [37], and AGLQFPVGR, a hepatoprotective peptide [36,37]. The gene discussed is ACE; the disease is obesity due to melanocortin 4 receptor deficiency.