EGNHS

EGNHS is a proteolytic targeting chimera (PROTAC) linker, which belongs to the alkyl/ether class and can be used to synthesize PROTAC molecules^[1]. PROTAC is a hybrid bifunctional small molecule compound, a "three-body" polymer - target protein ligand-linker-E3 ligand^[2]. EGNHS can form a cross-link between Lys232 and Lys241 of horseradish peroxidase C (HRP) and modify Lys174 without forming a cross-link^[3]. EGNHS is a cross-linker containing a reactive NHS ester (N-hydroxysuccinimide) end. NHS ester is a commonly used primary amine reactive group. It can react with primary amine groups to form a stable amide bond, which helps to effectively label the target molecule^[4]. EGNHS chemically modified porcine trypsin to obtain EG-trypsin, which improved the thermal stability and catalytic performance of trypsin^[5].

References:
[1] An S, Fu L. Small-molecule PROTACs: An emerging and promising approach for the development of targeted therapy drugs[J]. EBioMedicine, 2018, 36: 553-562.
[2] Li R, Liu M, Yang Z, et al. Proteolysis-targeting chimeras (PROTACs) in cancer therapy: present and future[J]. Molecules, 2022, 27(24): 8828.
[3] O'Brien A M, Ó'Fágáin C, Nielsen P F, et al. Location of crosslinks in chemically stabilized horseradish peroxidase: implications for design of crosslinks[J]. Biotechnology and bioengineering, 2001, 76(4): 277-284.
[4] Flynne W G. Biotechnology and bioengineering[M]. Nova Publishers, 2008.
[5] Colleary S, O'fagain C. Stability and catalytic properties of chemically modified pig trypsin[J]. Biocatalysis and Biotransformation, 2009, 27(5-6): 309-317.