Structural and Physicochemical Characteristics of Novel Basic Proteins Isolated from Duck Egg White
Bioscience, biotechnology and biochemistry
Novel basic proteins, duck basic protein small 1 (dBPS 1 ) and 2 (dBPS 2 ), 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 dBPS 1 showed 45% identity with dBPS 2 . The amino acid sequence of dBPS 2 was the same as cygnin, a small protein from black swan, and strongly homologous with meleagrin from turkey and chicken.
... and chicken. Phylogenic relationships implied that dBPS 1 and dBPS 2 share a common ancestry with cygnin and meleagrin. Based on MALDI-TOF mass spectra, the molecular masses of dBPS 1 and dBPS 2 were 4,373, and the 4,486 Da. pI of dBPS 1 and dBPS 2 elucidated by isoelectric focusing were 9.35 and 9.44. FT-IR spectra classified these proteins as () proteins. Both dBPS 1 and dBPS 2 , possessed high heat stability, Td 101.2 and 98.3 C. Indirect ELISA results showed that the dBPS 1 /dBPS 2 -related proteins were distributed in the oviduct and gallbladder.