Prion disinfection
AssigneeNovapharm Research (Australia) Pty Ltd
InventorsSteven Kritzler, Alex Sava, Michael Zalunardo
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Abstract
The invention relates to a methods and compositions for treating a surface, suspension or solution contaminated with a PrPScprion protein or a surrogate thereof. The methods and compositions employ a combination of one or more enzymes effective to cleave a prion protein to fragments having a non-infective molecular weight, and one or more agents selected to favour conformational unfolding of the PrPScprion protein while not denaturing the one or more enzymes.
Claims22
1 A method of disinfection comprising the steps of treating a surface, suspension or solution contaminated with a PrPSc prion protein or a surrogate thereof simultaneously with a combination of (1) one or more enzymes effective to cleave a prion protein to fragments having a non-infective molecular weight, and (2) one or more agents selected to favour conformational unfolding of the PrPSc prion protein while not denaturing the one or more enzymes.
2 A method according to claim 1 wherein the treatment is selected so as to result after cleavage in a predetermined percentage of the protein fragments having a molecular weight of less than a predetermined molecular weight.
3 A method according to claim 1 or claim 2 wherein at least 90% of the protein fragments after cleavage have a molecular weight of less than 27 kDa.
4 A method according to claim 1 or claim 2 wherein at least 90% of the protein fragments after cleavage have a molecular weight of less than 25 kDa.
5 A method according to claim 1 or claim 2 wherein at least 90% of the protein fragments after cleavage have a molecular weight of less than 23 kDa.
6 A method according claim 1, further including in the combination (3) one or more agents selected to promote or protect folding of the one or more enzymes, without preventing cleavage of the prion protein.
7 A method according to claim 6 wherein the conditions are selected to favour unfolding over refolding.
8 A method according to any one of the preceding claims wherein said one or more agents selected to favour conformational unfolding includes one or more agents selected from the group consisting of irradiation, electric field, magnetic field, energetic vibration and combinations thereof.
9 A method according to claim 8 wherein the energetic vibration is one or more of ultrasound, electromagnetic or mechanical vibration.
10 A method according to any one of the preceding claims wherein the one or more enzymes are selected from proteinases and enzymes possessing proteolytic activity.
11 A method according to any one of the preceding claims wherein the one or more agent selected to promote unfolding is selected from the group consisting of heat, pH, organic solvents of the kind which tend to denature proteins, chaotropic agents, surfactants tending to bind proteins, inorganic salts which are strong denaturants of proteins, agents which cause S—S bond scission, substances having a strong affinity for hydrophilic residues of amino acids, substances having a strong affinity for hydrophobic residues of amino acids, substances promoting adsorption on surfaces, anionic surfactants and combinations of the foregoing.
12 A method according to any one of claims 6 to 11 when dependant on claim 6 wherein the folding agent is selected from the group consisting of nucleophilic solvents, weakly protic stabilizing solvents, non ionic surfactants, ionic surfactants, zwitterionic and amphoteric surfactants, buffers, surface active homo-co-or block copolymers, sulphated compounds, deoxycholate, glycosaminoglycans and combinations of the foregoing.
13 A composition for treating a surface contaminated with a PrPSc prion protein or a surrogate thereof comprising (1) one or more enzymes selected effectively to cleave a prion protein to fragments having a non-infective molecular weight, and (2) one or more agents selected to favour conformational unfolding of the PrPSc prion protein while not denaturing the one or more enzymes.
14 A composition according to claim 13 wherein the one or more agents is selected so as to result after cleavage in a predetermined percentage of the protein fragments having a molecular weight of less than a predetermined molecular weight.
15 A composition according to claim 13 wherein the one or more agents is selected so as to result after cleavage in at least 90% of the protein fragments after cleavage having a molecular weight of less than 27 kDa.
16 A composition according to claim 13 wherein the one or more agents is selected so as to result after cleavage in at least 90% of the protein fragments having a molecular weight of less than 25 kDa.
17 A composition according to claim 13 wherein the one or more agents is selected so as to result after cleavage in at least 90% of the protein fragments having a molecular weight of less than 23% Da.
18 A composition according claim 13 further including one or more agents selected to promote or protect folding of the one or more enzymes, without preventing cleavage of the prion protein.
19 A method of treating a surface contaminated with a PrPSc prion protein or a surrogate thereof wherein the surface is treated with a composition according to any one of claims 13-18.
20 A method according to claim 19 wherein the surface is the surface of a medical or surgical instrument.
21 A method according to claim 19 wherein the surface is a food preparation or hospital work surface.
22 A method substantially as herein described with reference to any of the examples.