Biochemical properties of black drum and sheepshead seabream skin collagen.

Acid-soluble collagen (ASC) and pepsin solubilized collagen (PSC) were isolated from the skins of black drum (Pogonias cromis) and sheepshead seabream (Archosargus probatocephalus) harvested in the Gulf of Mexico coastal waters. The yields of ASCs on dry basis from black drum and sheepshead were estimated at 2.3 and 2.6%, and the yields of PSCs were 15.8 and 29.3%, respectively. Analyses of molecular weight profile, amino acid composition, and secondary structure showed that the skin collagens from both species were typical type-I collagen. The molecular mass of alpha(1) and alpha(2) subunits, as determined by SDS-PAGE using Tris-Acetate gels, was 127 kDa and 116 kDa, respectively. The amino acid composition of ASC and PSC for both species was closer to calf skin ASC than to cod skin ASC. Thermal denaturation temperatures, measured by melting point using circular dichroism, gave the following values: black drum ASC, 34.2 degrees C; sheepshead ASC, 34.0 degrees C; black drum PSC, 35.8 degrees C; sheepshead PSC, 34.3 degrees C. The literature value for the heat stability of calf skin collagen is 36.3 degrees C. The potentials of collagens from black drum and sheepshead skins in the functional food, healthcare, and pharmaceutical industries are discussed.