Isolation and characterization of acid and pepsin-solubilized collagen from the skin of sailfish (Istiophorus platypterus)

Acid-solubilized collagen (ASC) and pepsin-solubilized collagen (PSC) were extracted from the skin of sail fish (Istiophorus platypterus) with yields of 5.76% and 2.11% respectively, on the basis of wet weight. According to the electrophoretic pattern, ASC and PSC consisted of two different α chains (α1 and α2) and were characterized as Type I collagen. Peptide maps of ASC and PSC hydrolysed by Achromopeptidase from Achromobacter lyticus exhibited similar banding patterns with human-placenta collagen suggesting, sailfish collagen is a Type I collagen. Fourier transform infrared (FTIR) spectra of ASC and PSC were quite similar and the regions of amides A, I, II and III were 3422 and 3337, 1654 and 1646, 1560 and 1559 and 1240 cm− 1 respectively. FTIR results suggest that the pepsin hydrolysis did not affect the secondary structure of collagen, especially triple-helical structure. 1H NMR analysis revealed the presence of water molecules along with their corresponding singlet medium chemical shift of about 4.6 to 4.8 ppm in ASC and PSC. Scanning electron microscopy (SEM) studies confirmed the presence of collagen in the isolated, as fine globular filaments. Thus, possibility of sail fish collagen as an alternative source for mammalian collagen and also it could be used in nutraceutical and pharmaceutical industries.