Table 5.1 Molecular Probes heterobifunctional crosslinkers.

Cat # Crosslinker
Thiol (R–SH) Amine (R–NH2) Azide * (R–N3) Alkyne * Photoreactive †
S1553 succinimidyl acetylthioacetate (SATA) ‡ X X      
S1534 succinimidyl trans-4-(maleimidylmethyl) cyclohexane-1-carboxylate (SMCC) ‡ X X      
S1531 succinimidyl 3-(2-pyridyldithio)propionate (SPDP) X X      
E2247 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDAC) §   X      
P6317 N-((2-pyridyldithio)ethyl)-4-azidosalicylamide (PEAS; AET) ‡ X       X
A2522 4-azido-2,3,5,6-tetrafluorobenzoic acid, succinimidyl ester (ATFB, SE)   X     X
B1508 benzophenone-4-maleimide X       X
B1526 benzophenone-4-isothiocyanate   X     X
B1577 4-benzoylbenzoic acid, succinimidyl ester   X     X
I10188 iodoacetamide azide * X     X  
I10189 iodoacetamide alkyne * X   X    
C10413 Click-iT maleimide DIBO alkyne * X   X    
A10280 azido (PEO)4 propionic acid, succinimidyl ester *   X   X  
A10279 alkyne, succinimidyl ester *   X X    
C10414 Click-iT succinimidyl ester DIBO alkyne *   X X    
* Azides react with alkynes via the copper-catalyzed azide–alkyne cycloaddition reaction, as discussed in Click Chemistry—Section 3.1 (where these products are also described).
† Reacts nonspecifically with available sites upon UV illumination.
‡ These reagents contain cryptic thiols that are exposed by disulfide reduction (SPDP or PEAS) or deacetylation (SATA) and can be subsequently disulfide-coupled to other thiolated molecules or thioether-coupled to maleimides or iodoacetamides.
§ EDAC couples amines to carboxylic acids (Derivatization Reagents for Carboxylic Acids and Carboxamides—Section 3.4).