English to Spanish Tech/Engineering Chemistry; Chem Sci/Eng Chemistry

Hello,

What is the equivalent of "conjugate moiety"?

"A conjugate moiety is a non-proteinaceous or peptic moiety that can be attached to the antibody. The conjugate moiety may be linked to the antibody by covalent binding, affinity binding, intercalation, coordinate binding, complexation, association, blending, or addition, among other methods."

Thanks in advance!