Callinectin, an antibacterial peptide from blue crab (Callinectes sapidus Rathbun (1896)) hemocytes

Crustaceans do not possess a specific immune response system but instead, depend entirely on non-specific antimicrobial defenses such as phagocytosis, encapsulation and non-specific defense molecules. Previous work has revealed that blue crab, Callinectes sapidus Rathbun (1896), hemocytes contain a broad-spectrum, proteinaceous, antimicrobial activity. This paper describes the isolation of a novel, approximately 3.7 kd, heat-labile, basic, antibacterial peptide (designated Callinectin) which is responsible for the majority of this activity. A single step purification using low pressure cation exchange chromatography yielded a highly purified ({dollar}>{dollar}90%) material. Purity was confirmed by C{dollar}sb4{dollar}RP-HPLC, native gel electrophoresis, SDS-PAGE, capillary electrophoresis and mass spectral analysis. The partial amino acid sequence obtained via Edman degradation revealed no significant homology to other reported peptides in the BLAST program database.