Pre-activated proteins for labelling oligonucleotide probes
First Claim
1. An antibody or an enzyme reagent, pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of a thiol containing protein, said reagent being lyophilized from a buffered carbohydrate solution having a pH of from 6 to 8 which buffered solution has concentration of non-volatile salts of not more than 10 mM, so as to provided said reagent in dry solid form and being stable for at least 3 months against hydrolysis, polymerization and loss of label activity and of capacity to form conjugate by said covalent coupling.
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Abstract
Pre-activated stable protein reagents are provided. The reagents can be made by reaction of the protein and a heterobifunctional linker and have extended stability especially after lyophilisation. The reagents can be used in assay kits to form conjugates with proteins e.g. antibodies or polynucleotides e.g. oligonucleotides probes.
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Citations
19 Claims
- 1. An antibody or an enzyme reagent, pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of a thiol containing protein, said reagent being lyophilized from a buffered carbohydrate solution having a pH of from 6 to 8 which buffered solution has concentration of non-volatile salts of not more than 10 mM, so as to provided said reagent in dry solid form and being stable for at least 3 months against hydrolysis, polymerization and loss of label activity and of capacity to form conjugate by said covalent coupling.
- 8. A kit to enable the use of prepared conjugates comprising a pre-activated antibody or an enzyme reagent, pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of a thiol containing protein and instructions for use, said reagent being lyophilized from a buffered carbohydrate solution having a pH of from 6 to 8 which buffered solution has a concentration of non-volatile salts of not more than 10 mM, so as to provide said reagent in dry solid form and being stable for at least 3 months against hydrolysis, polymerisation and loss of label activity and of capacity to form conjugate by said covalent coupling.
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10. A method of making a conjugate which comprises reacting an antibody or an enzyme reagent, pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of a thiol containing protein with a thiolated polynucleotide or a thiol containing protein respectively, said reagent being lyophilized from a buffered carbohydrate solution having a pH of from 6 to 8 which buffered solution has a concentration of non-volatile salts of not more than 10 mM, so as to provide said reagent in dry solid form and being stable for at least 3 months against hydrolysis, polymerisation and loss of label activity and capacity to form conjugate by said covalent coupling, and reconstituting said lyophilized reagent in buffer before use.
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15. A reagent pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of a thiol containing protein, said reagent comprising a derivatized enzyme selected from the group consisting of alkaline phosphatase and horse radish peroxidase, said derivatization being by a reaction to give 1-3 substituents per enzyme molecule with a heterobifunctional cross-linking agent selected from the group consisting of:
- ##STR9## (SMCC) where R1 is H or SO3 Na;
##STR10## (MBS) where R2 is H or SO3 Na;
##STR11## (SMPB) where R3 is H or SO3 Na;
##STR12## (SIAB) where R4 is H or SO3 Na; and
##STR13## and said reagent being in dry solid lyophilised form from a buffered carbohydrate solution having a pH of from 6 to 8 which buffered solution has a concentration of non-volatile salts of not more than 10 mM, and being stable for at least 3 months against hydrolysis, polymerisation and loss of label activity and of capacity to form conjugate by said covalent coupling.
- ##STR9## (SMCC) where R1 is H or SO3 Na;
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16. A storage stable freeze dried reagent pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of thiol containing protein, said reagent comprising:
alkaline phosphatase derivatised by 1-3 molecules per phosphatase molecule of the heterobifunctional cross linking agent;
##STR14## wherein said reagent has been lyophilized from a phosphate buffered solution containing lactose and having a pH of from pH 7.2 to pH 7.8 which buffered solution has a concentration of non-volatile salts of not more than 10 mM, and being stable for at least 3 months against hydrolysis, polymerization and loss of label activity and of capacity to form conjugate by said covalent coupling.
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17. A storage stable freeze dried reagent pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of a thiol containing protein, said reagent comprising:
alkaline phosphatase derivatised by 1-3 molecules per phosphatase molecule of the heterobifunctional cross linking agent;
##STR15## wherein said reagent has been lyophilized from a phosphate buffered solution containing lactose and having a pH of from pH 7.2 to pH 7.8 which buffered solution has a concentration of non-volatile salts of not more than 10 mM, and being stable for at least 3 months against hydrolysis, polymerization and loss of label activity and of capacity to form conjugate by said covalent coupling.
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18. A storage stable freeze dried reagent pre-activated for covalent coupling to a thiol group of a thiolated polynucleotide or to a thiol group of a thiol containing protein, said reagent comprising:
horseradish peroxidase derivatised by 1-3 molecules per peroxidase molecule of the heterobifunctional cross linking agent;
##STR16## wherein said reagent has been lyophilized from a phosphate buffered solution containing lactose and having a pH of from pH 7.2 to pH 7.8 which buffered solution has a concentration of non-volatile salts of not more than 10 mM, and being stable for at least 3 months against hydrolysis, polymerization and loss of label activity and of capacity to form conjugate by said covalent coupling.
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19. In a process for making a conjugate of an enzyme and a polynucleotide or protein by the steps of
(a) derivatising the polynucleotide or protein to apply to it one or more pendant thiol groups; -
(b) derivatising the enzyme to apply to it one or more thiol-reactive groups; and (c) reacting the derivatised polynucleotide or protein with the derivatised enzyme; the improvement which comprises lyophilizing the derivatised enzyme in a buffered carbohydrate solution having a pH of from 6 to 8 which buffered solution has a concentration of non-volatile salts of not more than 10 mM so as to give a reagent stable for at least 3 months, storing it until required and reconstituting said reagent in buffer before use, whereby to decrease by one the number of chemical reaction stages at the time of making said conjugate.
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Specification