Abstract: Penaeidin belonged to a kind of the antibacterial peptide in innate immunity system,and it was also an immunity effector molecular what aquatic animals used to defend bacterial invasion. In this paper, Litopenaeus vannamei penaeidin-2 (PEN-2) was the research object, and the antibacterial functions were explored by studying the bacteria binding activity, protease activity inhibitory function, and antibacterial activity that were related to the antibacterial function. The results showed Litopenaeus vannamei PEN-2 possessed strong bacteria binding activity in vitro, and could inhibit the avtivity of secretory protease, but the antibacterial activity was very weak.

Key words: Litopenaeus vannamei; penaeidin; bacteria binding function; protease activity inhibitory function; antimicrobial activity