Magnificamide, a β-Defensin-Like Peptide from the Mucus of the Sea Anemone Heteractis magnifica, Is a Strong Inhibitor of Mammalian α-Amylases

Sea anemones' venom is rich in peptides acting on different biological targets, mainly on cytoplasmic membranes and ion channels. These animals are also a source of pancreatic alpha-amylase inhibitors, which have the ability to control the glucose level in the blood and can be used for the treatment of prediabetes and type 2 diabetes mellitus. Recently we have isolated and characterized magnificamide (44 aa, 4770 Da), the major alpha-amylase inhibitor of the sea anemone Heteractis magnifica mucus, which shares 84% sequence identity with helianthamide from Stichodactyla helianthus. Herein, we report some features in the action of a recombinant analog of magnificamide. The recombinant peptide inhibits porcine pancreatic and human saliva alpha-amylases with Ki's equal to 0.17 +/- 0.06 nM and 7.7 +/- 1.5 nM, respectively, and does not show antimicrobial or channel modulating activities. We have concluded that the main function of magnificamide is the inhibition of alpha-amylases; therefore, its functionally active recombinant analog is a promising agent for further studies as a potential drug candidate for the treatment of the type 2 diabetes mellitus.