Labeling proteins with 99m-Tc by ligand exchange

Abstract

Abstract A new method for labeling proteins with 99m-technetium: (1) Start with any volume of technetium (pertechnetate and saline) solution and add 0.1 ml of stannous solution (stannous fluoride-acetate solution) per 15-20 ml of saline. The stannous ions will reduce the pertechnetate to technetium IV. (2) Pour the solution onto a sterile Sephadex G-25 column, The reduced technetium (Tc-IV) will bind to the very top layer of Sephadex. (3) Wash the column with saline solution to remove any free pertechnetate or unusual species of technetium. (4) Add the protein in the minimum volume of water to the top of the Sephadex column. Wait 30 minutes. During this waiting period ligand exchange will occur and the technetium will become bound to the protein, but only to those sites on the protein that form a stronger ligand bond than the Sephadex. This means that the only product that will be formed will be technetium strongly bound to proteins. (5) Wash the labeled protein through the column by adding 1 cc of human serum albumin solution diluted 50/50 with ACD. (6) When this has all soaked into the column, add 5 cc of saline, which means that since the volume of the column is 5 cc there will be 6 cc of eluate. The last (or 6th) cc will contain the Tc-labeled human serum albumin. The impurities will remain on the column.

Inventors

• 👤 Buck A. Rhodes

Bibliographic Details