Purification of a novel antibacterial short peptide in earthworm Eisenia foetida. Acta Biochim Biophys Sinica

Abstract A novel antimicrobial short peptide was purified from earthworm (Eisenia foetida) by a five-step protocol including ammonium sulfate precipitation, ultrafiltration, DE-52 ion exchange chromatography, Sephadex G-10 column chromatography, and C-18 reversed-phase HPLC techniques. The purified peptide was applied to the MALDI-TOP MS to determine the molecular mass and was also subjected to TOF MS-MS analysis to determine the amino acid sequence. As a result, a novel antibacterial peptide, named OEP3121, was obtained, with the molecular mass of 510.8 Da and the sequence being “ACSAG”. Key words antibacterial peptide; earthworm; purification Earthworms live in an environment with abundant pathogens. These pathogens are, firstly, bacteria living in water or soil that are ingested during feeding or introduced into the body following injury. Parasites, particularly larval forms, which represent the dissemination phase, are another important group of potentially pathogenic agents. During the course of evolution, earthworms hav