N-Hydroxysuccinimidyl ester

OTcp 2,4,5-trichlorophenyl ester ONSu N-hydroxysuccinImidyl ester N azide... 

According to the manufacturer s instructions, the density of the activated ester (N-hydroxysuccinimidyl ester) on the beads was 16-23 gmol/mL of swollen beads. 

The PLL- -PEG copolymers were synthesized according to a previously described method (1, 2). Briefly, poly(L-lysine) hydrobromide (PLL-HBr, MW 20 kDa Sigma, St, Louis. MO) was dissolved in a 50 mM sodium borate buffer solution, followed by filter sterilization of the solution (0.22 m pore-size filter). The N-hydroxysuccinimidyl ester of methoxypolyiethylene gly-col)propionic acid (SPA-PEG Shearwater Polymers. Inc., Huntsville, AL) was then added to the dissolved PLL-HBr. The reaction was allowed to proceed for 6 h at room temperature, after which the reaction mixture was dialyzed (SpectraPor, MW cutoff size... 

HSAB (N-hydroxysuccinimidyl-4-azidobenzoate) is a heterobifunctional reagent containing an amine-reactive NHS ester on one end and a photoreactive phenyl azide group on the other end... 

Higher yields of L-[amide- N]asparagine have been obtained by a rapid, nonenzymatic method. The free -carboxyl group of L-a-N-f-Boc-a-t-Bu-aspartic acid is activated with N-hydroxysuccinimide to yield L-a-N-f-Boc-a-t-Bu- -N-hydroxysuccinimidyl aspartic ester, which is re-fiuxed for 10 min with [ N]anunonia. Hydrolysis for 1 min in IN HCl yields up to 30-40% of L-[ami fe- N]asparagine, which is then purified by cation-exchange column chromatography (31). 

The most commonly used visible fluorophores are the rhodamine and fluorescein analogues. These dyes can be derivatized with either an isothiocyanato group (-NCS) or an N-hydroxysuccinimidyl (NHS) ester functionality for covalent labelling at the amino group of proteins or amino-functionalised nucleotides (Fig. 14.1). A number of dyes containing reactive groups are commercially available and they are as a rule inexpensive. 

For the covalent approach, standard protocols include bioconjugation techniques that have been routinely used in protein derivatization (Ma et al., 2012). The most widely used reactions include the reactive side chains of lysine (Lys), cysteine (Cys), aspartic acid (Asp), glutamic acid (Glu), and tyrosine (lyr) residues, which are available to form biocompatible covalent bonds (Fig. 15.5A). Lysine residues and N-termini provide reactive moieties in primary amines form (R-NH ) that have been mainly targeted with A-hydroxysuccinimidyl-esters (NHS-esters) or NHS-ester sulfate derivatives (Smith et al., 2013). 

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