Technetium-99m labeling of proteins
AssigneeAkzo N.V.
InventorRamaswamy Subramanian
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Abstract
A method for attaching technetium-99m to proteins using reducing metal reagents to achieve binding to high affinity binding sites and high specific activity. The reagents play a dual role under the given experimental conditions by reducing disulfide bonds in the proteins to sulfhydral groups suitable for binding to technetium, and reducing pertechnetate from Tc(VII) to Tc(III) or Tc(V). Reduction of disulfide on the protein is conducted initially with an excess of reducing metal reagent, a pertechnetate reagent is added at the end of the protein reduction reaction and allowed to continue to reduce the technetium. Thereafter a chelator scavenger is added to remove poorly bound or unbound technetium.
Claims6
A method for labeling a protein selected from the group consisting of an antibody or a F(ab').sub.2 antibody fragment with technetium-99m, comprising the following steps in the order presented:
- first, contacting the protein with a reducing metal bound to a glucaric acid salt by a covalent or a coordinate bond in reaction mixture, whereby one to three sulfhydryl groups on the protein are reduced to disulfides, and,
- second, adding pertechnetate to the reaction mixture and incubating to bind reduced technetium-99m to the protein, wherein the protein is selected from the group consisting of an antibody and a F(ab').sub.2 antibody fragment, and the labeling of the protein with the technetium-99m is at least 90%.
Dependencies are inferred from the claim text.