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Lytic Antimicrobial Activity of Hen Egg White Lysozyme Immobilized to Polystyrene Beads
Author(s) -
Wu Y.,
Daeschel M.A.
Publication year - 2007
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1750-3841.2007.00529.x
Subject(s) - lysozyme , chemistry , hydrolysis , polystyrene , michaelis–menten kinetics , chromatography , peptide , egg white , immobilized enzyme , enzyme , lysine , amino acid , enzyme assay , biochemistry , polymer , organic chemistry
Lysozyme [EC 3.2.1.17] was covalently attached to polystyrene resin beads by the sole histidine residue (His‐15) through peptide spacers of various lengths. The spacers were amino acid chains composed of 6‐aminocaproic acid synthesized with the solid phase peptide synthesis method. Immobilized lysozyme with a spacer length of three 6‐aminocaproic acid units (2736 U/g resin with a protein load of 2.21 mg/g resin) displayed the greatest degree of hydrolytic activity against lyophilized Micrococcus lysodeikticus cell wall preparations. Enzymatic activity of immobilized lysozyme was 14.2% of that of the free enzyme. Preparations with longer spacers yielded higher total activity yet the retained activity was constant at about 14% level. A control that consisted of randomly coupled lysozyme to polystyrene beads without an amino acid spacer gave an enzyme activity of 158 U/g with a protein load of 1.24 mg/g resin which equated to 1.4% retained activity. Properties of the immobilized lysozyme system were studied, including stability and activity against soluble compared with insoluble substrates. A kinetics study of the immobilized lysozyme using Eadie–Hofstee plot parameters suggested significant external diffusion effects indicative of deviation from classic Michaelis–Menten kinetic behavior.