Chemical and Immunological Properties and Amino Acid Sequences of Three Lysozymes from Peking-Duck Egg White

Abstract

Three lysozymes (DLs-1, -2, and -3) were purified from Peking-duck egg white by adsorption on CM-Sephadex C-25 resin, followed by CM-Sephadex C-25 and Sephadex G-50 column chromatographies. The three enzymes each moved as a single band, but showed different electrophoretic mobilities, on disc-polyacrylamide gel electrophoresis at pH 4.1. Final yields of DL-1, DL-2, DL-3 were 18.2%, 22.0%, and 6.0%, respectively, from the crude material adsorbed on CM-Sephadex resin. The enzymatic activities of DL-1, DL-2, and DL-3 were 1.53, 1.52, and 1.34 times that of hen egg white lysozyme, respectively, using Micrococcus lysodeikticus cell wall as a substrate at pH 6.2 and 37 degrees C. All the DLs lacked histidine and their amino acid compositions differed from each other by a few amino acid exchanges. The amino acid sequences of DL-2 and DL-3 differed from that of DL-1 by two displacements (Ser-37 to Gly and Gly-71 to Arg) and three displacements (Pro-79 to Arg in addition to the same substitutions), respectively. In comparison with Duck II and Duck III lysozymes from Kaki-duck (Hermann and Jollès (1970) Biochim. Biophys. Acta 200, 178-179; Hermann et al. (1971) Eur. J. Biochem. 24, 12-17) as regards amino acid sequences, Duck II is identical to DL-1 except for one displacement of Gln-57 in DL-1 to Glu in Duck II, while Duck III is rather different from our three lysozymes. All DLs gave single precipitin lines with any rabbit antisera against DLs and each precipitin line fused completely with that of any of the DLs in Ouchterlony double diffusion tests. However, the radiobinding inhibition assay showed that some anti-DL antisera clearly discriminated fine differences among the three DLs. The displacement at residue 79 (Pro in equilibrium Arg) gave the clearest immunological difference among the three kinds of displacements found in DLs.

Antimicrobial Activity of Duck Egg Lysozyme against Salmonella enteritidis

“…It may be due to the differences of amino acid composition between these two Lzs. Compared with cLz, the contents of arginine, valine and tyrosine residue dLz were higher by a few residues, while those of aspartic acid, alanine and phenylalanine residues were lower by two, one and two residues, respectively (Kondo, 1982). The difference of arginine content in both Lz was also presented in other report.…”

“…Thus, these two bands were confirmed as dLz. The difference of these two peaks may be due to the multiple forms of dLz that have been mentioned in previous works (Prager et al, 1971;Hermann et al, 1973;Kondo et al, 1982). After being reduced by 2 mM DTT and trapped free sulfhydryl group with IAM, the lytic activity of dLz against M. luteus decreased as a function of reduction time ( Fig.…”

“…The last two displacements induce the conformational change of dLz from -turn to random coil (Prager et al, 1971;Hermann et al, 1973;Kondo et al, 1982).…”

Structural and Physicochemical Characteristics of Novel Basic Proteins Isolated from Duck Egg White

“…Investigation of the amino acid sequences of small basic proteins in many species might provide valuable information in the relation of structures and functions for those proteins, as in the case of lysozyme, [13][14][15] cystatin 16) and ovostatin. 17) It has been found that duck EW lysozyme shows a difference in amino acid sequence from chicken lysozyme.…”

“…Duck lysozyme contains three isoforms with higher enzymatic activity than that of chicken lysozyme, which has only one isoform. [13][14][15] Cystatin from duck EW presents glycosylated and phosphorylated properties, while chicken cystatin is lacking in both properties. 16) Differences y To whom correspondence should be addressed.…”