Method for the determination of proteins and polypeptides

Abstract

A process comprising contacting particles of water insoluble polymers to which have been bound antibodies, by means of covalent bonds, against the protein or polypeptide to be determined, wherein a certain quantity of the protein or polypeptide is labeled with a radioactive isotope, whereupon the particles, subsequent to the reaction between the protein or the polypeptide and the antibodies attached to the particles are separated from the sample liquid and the radioactivity of the particle material and/or in the liquid is determined.

What is claimed is: 
     
       1. A method for the determination of a member selected from the group consisting of proteins and polypeptides in aqueous samples, which comprises contacting particles of water insoluble polymers to which have been bound, by covalent bonds, antibodies against the said member to be determined, with the aqueous sample containing said member and with the same member labelled with a radioactive isotope to bind part of said labelled member and unlabelled member to said antibodies to produce a two-phase system comprising a solid phase comprising said bound part of labelled member and unlabelled member and a liquid phase comprising unbound labelled member and unlabelled member, separating the two phases from each other, and measuring the radioactivity of at least one of the said solid and said liquid phases, the value of said radioactivity being each a function of the concentration of the said member in the aqueous sample. 
     
     
       2. A method as claimed in claim 1, wherein the solid phase is washed with an aqueous liquid before measuring the radioactivity of said phase. 
     
     
       3. A method as claimed 1, wherein the determination is effected quantitatively by comparing the measured value of the radioactivity with a standard curve. .Iadd. 4. A method as claimed in claim 3, wherein said antibodies have been covalently bound to said particles under conditions sufficiently mild to ensure that the reactivity of said antibodies does not substantially decrease. .Iaddend..Iadd. 5. A method as claimed in claim 4, wherein said covalent bonds are formed through a group of the formula --NH·CS·NH--, --NH·CO·NH--, or --N=N--. .Iaddend..Iadd. 6. A method as claimed in claim 5, wherein said group is --NH·CS·NH--. .Iaddend..Iadd. 7. A method as claimed in claim 3, wherein said water-insoluble polymers contain at least one reactive group selected from the group consisting of amino, hydroxyl and carboxyl. .Iaddend..Iadd. 8. A method as claimed in claim 7, wherein said reactive group is hydroxyl. .Iaddend..Iadd. 9. A method as claimed in claim 7, wherein said reactive group is amino. .Iaddend..Iadd. 10. A method as claimed in claim 3, wherein said polymer is obtained by crosslinking a material selected from the group consisting of carbohydrates, sugar alcohols, and polyvinyl alcohol, with a bifuctional compound of the formula X--R--Z, wherein X and Z are each independently halogen or epoxy, and R is an aliphatic radical containing from 3 to 10 carbon atoms. .Iaddend..Iadd. 11. A method as claimed in claim 10, wherein said material is dextran and said bifunctional compound is epichlorohydrin. .Iaddend..Iadd. 12. A method as claimed in claim 3, 
     
     
        wherein said member is a plasma protein. .Iaddend..Iadd. 13.  A method as claimed in claim 3, wherein said member is an enzyme. .Iaddend..Iadd. 14. A method as claimed in claim 3, wherein said member is a hormone. .Iaddend..Iadd. 15. A method as claimed in claim 3, wherein said member is insulin. .Iaddend..Iadd. 16. A method as claimed in claim 3, wherein said member is a gonadotropin. .Iaddend..Iadd. 17. A method as claimed in claim 3, wherein said member is growth hormone. .Iaddend..Iadd. 18. A method as claimed in claim 3, wherein said member is ACTH. .Iaddend..Iadd. 19. A method as claimed in claim 3, wherein said member is thyrotropin. .Iaddend..Iadd. 20. A method as claimed in claim 3, wherein said member is parathormone. .Iaddend..Iadd. 21. A method as claimed in claim 3, wherein said aqueous sample is from blood serum. .Iaddend..Iadd. 22. A method as claimed in claim 3, wherein said aqueous sample is from urine. .Iaddend..Iadd. 23. A method as claimed in claim 3, wherein said radioactive isotope is I 125 , I 131 , C 14 , or H 3 ..Iaddend.