NHS ester-maleimide cross-linkers

Activation of Enzymes with NHS Ester-Maleimide Cross-linkers... 

NHS Ester-Maleimide Heterobifunctional Cross-linker-Mediated Hapten-Carrier Conjugation... 

Succinimidyl-4-(N-maleimidomethyl)cyclohexane-l-carboxylate (SMCC) is a heterobifunctional cross-linker with significant utility in cross-linking proteins, particularly in the preparation of antibody-enzyme and hapten-carrier conjugates (Hashida and Ishikawa, 1985 Dewey et al., 1987). The NHS ester end of the reagent can react with primary amine groups on proteins to form stable amide bonds. The maleimide end of SMCC is specific for coupling to sulfhydryls when the reaction pH is in the range of 6.5-7.5 (Smyth et al., 1964) (Fig. 158). 

Succinimidyl-4-(p-maleimidophenyl)butyrate (SMPB) is a heterobifunctional analog of MBS containing an extended cross-bridge (Chapter 5, Section 1.6). The cross-linker has an amine-reactive NHS ester on one end and a sulfhydryl-reactive maleimide group on the other. Conjugates formed using SMPB thus are linked by stable amide and thioether bonds. 

The most common type of heterobifunctional reagent used for the activation of lipid components includes the amine- and sulfhydryl-reactive cross-linkers containing an NHS ester group on one end and a maleimide, iodoacetyl, or pyridyl disulfide group on the other end (Chapter 5, Section 1). Principle reagents used to effect this activation process include SMCC (Chapter 5, Section 1.3), MBS (Chapter 5, Section 1.4), SMPB (Chapter 5, Section 1.6), SIAB (Chapter 5, Section 1.5), and SPDP (Chapter 5, Section 1.1). 

IJ.2.3.2.1.2. 4-(N-Maleimidomethyl)-cyclohexane-l-carboxylic acid N-hydroxysuccinimide ester (CHM-NHS) a stable maleimide crosslinker. Ishikawa et al. (1978) synthesized alternative maleimide compounds of which CHM-NHS was particularly stable (decomposition rate less than 4% in 2 h at 30°C at pH 7.0, compared to 53% for OPDM and MBS. This cross-linker has been adopted successfully for the conjugation of GOase, APase, and POase (Yoshitake et... 

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