Biotech Values

[jellybean]

An antibody is made up of four separate amino acid chains folded together and linked by disulfide bonds. The linker and conjugate are added to specific amino acids within those chains after production of the mature antibody. The linker is attached at a specific amino acid residue, often a cysteine, and since there are 4 separate protein chains, the targeted sites are multiples of four. For the SGEN antibody, the conjuation occurs at the amino terminus of the protein with a maximum of 8 possible drug additions but the average is 4 molecules/antibody. The variability comes when conjugation is not complete. I don't know where T-DM1 adds the conjuage.