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Environmental fate & pathways

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Lysozyme hydrochloride structure is sensitive to pH changes. The lysozyme enzyme isoelectric point has been reported at 10.5-11 (Blake et al., 1967), due to the preponderance of basic amino acid residues that confers a basic polypeptide character to the molecule. Depending on the pH conditions, lysozyme can polymerise (in biochemical sense, i.e. forming super molecules on the basis of non-covalent interactions): the dimers predominate in the pH range of 5 - 9 with the loss of the proton from the monomer. At low lysozyme concentrations there is monomer-dimer equilibrium; at higher concentrations the dimers are prevalent (Barbara and Pellegrini, 1976). The dimer form maintains the enzymatic activity.

No specific information exists on the abiotic degradation of lysozyme hydrochloride in the environment via hydrolysis or photolysis. However, considering that any enzyme general has a great biodegradation potential, possible abiotic degradation mechanisms is expected to be of lower significance compared to biodegradation process.

Lysozyme hydrochloride, as enzyme, belongs to the protein class of substance; it is known that the general degradation pathway of proteins is a stepwise process starting with the splitting of peptide bonds in the protein polymer by proteolytic enzymes (proteases) forming lower-molecular oligopeptides, which are subsequently degraded by peptidases to the monomeric amino acids.

In some cases enzymes derived from of new technologies might have increased stability and therefore altered biodegradability potential; nevertheless, this is not the case of the lysozyme hydrochloride. Lysozyme hydrochloride preserves the functionality and the reactivity potential of the precursor lysozyme, thus this implies that the substance characterization is not significantly altered and the environmental fate and pathway is not significantly impacted.

The substance is expected to be characterized by a low potential for adsorption, on the basis of its negative partition coefficient octanol-water.

Furthermore, based on the physicochemical properties, lysozyme hydrochloride is expected to not evaporate from the water surface into the atmosphere.

REFERENCE

Barbara L. and Pellegrini R. (1976). Fleming's Lysozyme : biological significance and therapeutic applications. Torino : Minerva medica. Monograph.

Blake C.C.F. Mair G.A., North A.C.T., Philips D.C., Sarma V.R. (1967). On the conformation of the hen egg-white lysozyme molecule. Proc. Roy. Soc.(London) ser. B, 167, 365.