Isolation and Characterization of Collagen from the Skin of Malaysian catfish (Hybrid Clarias sp.)

Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) were isolated from the skin of hybrid Clarias sp. with the yields of 18.11 +/- 0.32 and 26.69 +/- 0.54% (wet weight basis), respectively. Both collagens were characterized as type I collagen, containing alpha 1 and alpha 2 chains. Presence of high molecular weight crosslinks were observed in the gel electrophoresis of both collagens. Fourier transform infrared spectra of both collagens were almost similar, suggesting that pepsin hydrolysis did not disrupt the triple helical structure. The amino acid analysis showed glycine was the most abundant, with 207/1000 and 223/1000 residues present in ASC and PSC, respectively. The amounts of imino acids were 185/1000 residues for both. Thermal denaturation temperatures were determined to be 31.5 and 31.0 degrees C, respectively. Both collagens exhibited high solubility in acidic pH (1-5) and below 4% (w/v) NaCl concentration.