Isolation and characterization of pepsin-soluble collagen from abalone (Haliotis discus hannai) and preparation of a polyclonal antibody

Abalone mantle is the main by-product from abalone industry which is at a low utilization rate. The characterization of collagen from the abalone adductor and mantle was studied, for providing a theoretical foundation for processing of abalone. Purification and characterization of pepsin-soluble collagen from adductor (PSC1) and mantle (PSC2) of abalone (Haliotis discus hannai) were conducted. A polyclonal antibody was prepared against pepsin-soluble collagen from abalone adductor (PSC1). The results of SDS-PAGE suggested that the structures of PSC1 and PSC2 were (α₁)₃ and the molecular weight of α₁ chain was approximately 140 ku, which was the characteristic of typeⅠcollagen from aquatic invertebrates. Peptide mass fingerprinting (PMF) of PSC1 analysis obtained 6 peptide fragments including 75 amino acid residues which were identical with collagens from H. discus with 100% identity and H. tuberculata with 88% identity, suggesting PSC1 is collagen. Amino acid composition analysis showed that PSC1 and PSC2 had similar composition, while the amino acid content of them were lower than calf skin collagen by acid extraction. Circular dichroism (CD) spectrum analysis demonstrated a rotatory maximum at 220 nm and a negative peak at 197 nm of PSC1 and PSC2 solution, which were typical characteristics of the collagen triple helix structure. FTIR spectra further confirmed that both PSC1 and PSC2 have similar triple helical structure. According to Western blot analysis of collagens from 4 kinds of aquatic animals, the polyclonal antibody only positively reacted with α, β and γ chains of PSC1 and PSC2 from abalone, whereas no reactivity against collagens from Oreochromis niloticus, Cyprinus carpio and Stichopus japonicas was identified, indicating high specificity of the polyclonal antibody.