The synthetized peptides exhibited in vitro antioxidant activity through radical scavenging, ACE inhibitory activity, anti-diabetic effects through inhibition of α-amylase, α-glucosidase, and DPP-IV, and/or obesity modulatory ability by inhibition of pancreatic lipase. The gene discussed is PNLIP; the disease is obesity due to melanocortin 4 receptor deficiency.