APN-Maleimide is a bifunctional crosslinker for thiol-to-thiol coupling. The coupling can be performed with high selectivity in biological medium using mild reaction conditions. Due to kinetic resolution the first thiol reacts exclusively with maleimide residue producing the protein-APN conjugate. This conjugate can be readily coupled with thiol-containing molecules.
Standard protein labeling procedure (cysteine labeling).
Dissolve the protein in the appropriate buffer* with pH 6.5-9.0 (e.g. PBS) at 1-10 mg/mL concentration.
Apply the appropriate amount of the stock solution of the reagent (1-5 molar eq. per free cysteine residue).
Incubate at room temperature for 10 minutes.
If necessary, purify the protein-APN conjugate using SEC or ultrafiltration.
The conjugate can be readily coupled with thiol-containing substrates by incubating the components in aqueous buffer (pH 6.5-9.0) at ambient temperature for 2 hours.