Comparison of Physicochemical and Structural Properties of Acid-Soluble and Pepsin-Soluble Collagens from Blacktip Reef Shark Skin

Abstract

Fish collagen has been widely used in tissue engineering (TE) applications as an implant, which is generally transplanted into target tissue with stem cells for better regeneration ability. In this case, the success rate of this research depends on the fundamental components of fish collagen such as amino acid composition, structural and rheological properties. Therefore, researchers have been trying to find an innovative raw material from marine origins for tissue engineering applications. Based on this concept, collagens such as acid-soluble (ASC) and pepsin-soluble (PSC) were extracted from a new type of cartilaginous fish, the blacktip reef shark, for the first time, and were further investigated for physicochemical, protein pattern, microstructural and peptide mapping. The study results confirmed that the extracted collagens resemble the protein pattern of type-I collagen comprising the α1, α2, β and γ chains. The hydrophobic amino acids were dominant in both collagens with glycine and hydroxyproline as major amino acids. From the FTIR spectra, α helix (27.72 and 26.32%), β-sheet (22.24 and 23.35%), β-turn (21.34 and 22.08%), triple helix (14.11 and 14.13%) and random coil (14.59 and 14.12%) structures of ASC and PSC were confirmed, respectively. Collagens retained their triple helical and secondary structure well. Both collagens had maximum solubility at 3% NaCl and pH 4, and had absorbance maxima at 234 nm, respectively. The peptide mapping was almost similar for ASC and PSC at pH 2, generating peptides ranging from 15 to 200 kDa, with 23 kDa as a major peptide fragment. The microstructural analysis confirmed the homogenous fibrillar nature of collagens with more interconnected networks. Overall, the preset study concluded that collagen can be extracted more efficiently without disturbing the secondary structure by pepsin treatment. Therefore, the blacktip reef shark skin could serve as a potential source for collagen extraction for the pharmaceutical and biomedical applications.

Extraction and Characterization of Pepsin- and Acid-Soluble Collagen from the Swim Bladders of Megalonibea fusca

“…Relative to dry swim bladder weight, the respective yields of ASC and PSC were 33.38% and 84.79%, suggesting that pepsin was able to markedly enhance extraction efficiency, in line with prior reports [ 15 , 16 , 17 ]. This is at least partially attributable to the covalent telopeptide crosslinking of collagen molecules, as pepsin can cleave telopeptide residues to enhance overall collagen solubility [ 18 ].…”

“…Absorption peaks at ~3294 cm −1 and ~3286 cm −1 correspond to the respective N-H stretching vibration absorption peaks for ASC and PSC amide A, confirming the presence of hydrogen bonds [ 34 , 35 ]. Amide B peaks corresponding to asymmetrical CH 2 stretching were evident at 3076 cm -1 and 3072 cm −1 [ 16 ]. The amide I, II, and III bands have been reported to be associated with the triple-helical structure of collagen fibrils.…”

Extraction, Characterization and Osteogenic Activity of a Type I Collagen from Starfish (Asterias amurensis)

“…The UV absorption peak of collagen is generally in the range of 220–250 nm, which may be related to the groups C=O, –COOH, CONH 2 in the collagen polypeptide chain [ 16 ]. The weak absorption at 280 nm in the UV spectrum of AAC may be due to the presence of tyrosine [ 25 ].…”

Isolation and Biochemical Properties of Type II Collagen from Blue Shark (Prionace glauca) Cartilage

“…The isolation of BSCII was based on the method of Phanat et al and Ge et al [ 36 , 50 ] with modifications. All operations were carried out at 4 °C.…”

“…The FTIR spectra of BSCII were determined using a Fourier transform infrared spectrometer (L1050050 Spotlight 400, PerkinElmer Co., Wellesley, MA, USA), following the method of Ge et al [ 50 ] with slight modifications. Next, 2 mg of freeze-dried BSCII was placed on the sample table of the instrument.…”