The Microscale Protein Labeling Kits use an amine-reactive fluorophore or biotin to covalently attach the label to the protein or IgG antibody. Once formed, the covalent bond between the label and the protein is extremely stable; you are using the same chemistry we use to prepare our own primary and secondary conjugates.
Unlike our other antibody labeling kits, these kits have been optimized for labeling proteins between 12 and 150 kDa, and so have utility in labeling antibodies as well as other proteins in that size range.
Any stabilizing proteins (i.e., BSA), must be removed prior to the labeling reaction. Convenient spin columns purify the labeled protein (Figure 1) with yields between 60 and 90%, depending on the molecular weight of the starting material. The entire labeling and purification procedure can be completed in as little as 2 hours—everything needed to perform three conjugations is provided in the kits
Figure 1. Spin filter. (A) An empty filter showing the separate parts. (B) Appearance of the resin bed after centrifugation in a fixed-angle rotor or swinging bucket rotor.