Introduction 

The Borenpharm Alkyne-PEG-acid and Alkyne-PEG NHS ester is a triple bond labeling reagent that reacts with primary and secondary amines. The terminal alkyne group reacts with an azide to produce a stable triazole, also

referred to as the Cu(I)‐catalyzed click reaction. This reaction possesses extreme selectivity and biocompatibility, such that the complimentary reagents can form covalent bonds within richly functionalized biological systems, in some cases, living organisms. Alkyne-PEG NHS ester must be first dissolved in a minimal amount of an organic solvent, such as dimethylsulfoxide (DMSO) or dimethylformamide (DMF) and then added to the buffer containing the protein or other molecule. The reagent forms an emulsion that allows the reaction to proceed.

Important Product Information

Alkyne-PEG NHS ester is moisture-sensitive. Store the vial of biotin reagent at 4°C with desiccant. To avoid moisture condensation onto the product, equilibrate vial to room temperature before opening.

As directed in the procedure, dissolve the Alkyne-PEG NHS ester reagent immediately before use. The NHS moiety readily hydrolyzes and becomes non-reactive; therefore, weigh and dissolve only a small amount of the reagent at a time, and do not prepare stock solutions for storage. Discard any unused reconstituted reagent.

Avoid buffers containing primary amines (e.g., Tris or glycine) as these will compete with the reaction. If necessary, dialyze or desalt to exchange the protein sample into an amine-free buffer such as phosphate-buffered saline (PBS).

When Pegylating proteins in solution, excess non-reacted PEG linker is easily removed by size exclusion using either desalting columns or dialysis (Additional Information). A 10mL desalting column is best suited for processing Pegylation reactions involving 1-10mg of protein in approximately 0.5-2mL. For smaller amounts of protein and/or smaller reaction volumes, both the Pegylation reaction and subsequent buffer exchange may be performed in a single Thermo Scientific Slide-A-Lyzer MINI Dialysis Unit. For larger reaction volumes than can be processed with a desalting column, either split the sample between two columns or use an appropriate Slide-A-Lyzer® Dialysis Cassette.