The invention relates to compounds of general structure (1): Q-(L1)n-(L2)o-(L3)p-(L4)q-D (1), wherein Q is a click probe; D is a cytotoxin containing an enediyne moiety; L1, L2, L3 and L4 are each individually linkers that together link Q to D; n, o, p and q are each individually 0 or 1, provided that n+o+p+q=1, 2, 3 or 4, wherein D comprises a functional moiety (21): wherein R12═C1-3-alkyl, the wavy line indicates the connection to the remainder of the cytotoxin, and wherein D is conjugated to (L4)q by replacing the amine H atom, and to conjugates obtainable by reacting the compound according to the invention with a protein comprising a click probe F capable of reacting with click probe Q in a click reaction. The invention further relates to a bioconjugate according to general structure (2): Pr-[(L6)-Z-(L1)n-(L2)o-(L3)p-(L4)q-D]xx (2), wherein Z is a connecting group that is formed in a click reaction, L6 is a linker that links Z to Pr and Pr is a (glyco)protein.