Myeloma proteins affinity labeling

Goetzl, E.J. Metzger, H. (1970). Affinity labeling of a mouse myeloma protein which binds nitrophenyl ligands. Sequence and position of a labeled tryptic peptide. Biochemistry 9, 3862-3871. 

Affinity Labeling Studies an Myeloma Proteins and Antibodies... 

Vn. AFFINITY LABELING OF ANTIBODY MOLECULES OR MYELOMA PROTEINS WITH ANTIBODY ACTIVITY... 

D. Affinity Labeling of Myeloma Proteins with Antibody Activity... 

Potentially, there are many significant advantages associated with affinity labeling of myeloma proteins, as compared to conventional antibodies. (The myeloma proteins must, of course, have antihapten activity.) The homogeneity of the protein permits detailed sequence analysis and thus a precise localization of the affinity label. In addition, one might expect that in theory all of the sites of the myeloma protein population could be labeled. In the case of conventional antibodies this has generally not been possible because of heterogeneity of active sites evidently not all sites contain an appropriate side chain, or some side chains subject to attack by the affinity label are not sterically available. 

Cross-linking did not occur if the protein was not affinity labeled. This experiment indicated that portions of the H and L chains are in close proximity in or very near the hapten-binding site of the myeloma protein. The side chain involved on the H chain was not identified. 

Protein 460, another mouse myeloma protein with anti-Dnp activity, was also affinity labeled by compound BADE (136). The label was found on the L chain, as in protein 315, but attached to a lysyl rather than a tyrosyl side chain. The locus of attachment was in a hypervariable region, at position 54. 

A photoactivated molecule was exploited for affinity labeling of myeloma proteins by Rosenstein and Richards (137). The molecule, 1-methyl-2,4-naphthaquinone- H-3-thioglycollyl diazoketone, abbreviated H-menadione diazoketone or H-MenDK, has the following structure. 

Myeloma proteins have been affinity labeled (Chapter 2). As is... 

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