| Abstract: | Novel basic proteins, duck basic protein small 1 (dBPS1) and 2 (dBPS2), were isolated from duck egg white by cation-exchange and gel filtration chromatography. Protein sequence analyses indicated that they possessed 39 amino acid residues with three disulfide bonds. The amino acid sequence of dBPS1 showed 45% identity with dBPS2. The amino acid sequence of dBPS2 was the same as cygnin, a small protein from black swan, and strongly homologous with meleagrin from turkey and chicken. Phylogenic relationships implied that dBPS1 and dBPS2 share a common ancestry with cygnin and meleagrin. Based on MALDI-TOF mass spectra, the molecular masses of dBPS1 and dBPS2 were 4,373, and the 4,486 Da. pI of dBPS1 and dBPS2 elucidated by isoelectric focusing were 9.35 and 9.44. FT-IR spectra classified these proteins as (β) proteins. Both dBPS1 and dBPS2, possessed high heat stability, Td 101.2 and 98.3 °C. Indirect ELISA results showed that the dBPS1/dBPS2-related proteins were distributed in the oviduct and gallbladder. |
