Labeling Chemistry
Protein labeling reagents are used for various assays that are coupled with antigen-antibody reactions. Of these, fluorescent, biotin, and enzyme labeling reagents are used most frequently for antibody labeling. Most protein labeling reagents have similar reactive sites, such as succinimidyl ester (NHS) for amino groups and maleimide or bromoacetamide for sulfhydryl groups. Dojindo offers a wide variety of protein labeling kits. These kits can be used to prepare conjugates with enzymes, fluorophore, and biotin. Dojindo’s labeling kits contain centrifugal filtration tubes, which are used for protein purification, conjugation reaction, condensation, and buffer exchange.
Our newest addition, Ab-10 Rapid Labeling Kits allows simple and rapid preparation of enzyme or fluorophore conjugates with a smaller quantity of antibody.
Antibody labeling procedure comparison
*Ab-10:Some additives in the antibody solution may interfere with the labeling if the concentration is too high. The maximum compatible concentrations of such additives are indicated in on Table 2.
Table 2 Compatible concentrations of the additives
What are Cross-Lining Reagents ?
Cross-Linking Reagents are widely used for both immune assays and protein analysis. Dojindo offers a variety of reagents that have different spacer arm lengths or functional groups. The two different types are:
- Hetero-bifunctional Reagents contain different reactive groups on each end of the spacer arm. Dojindo offers the reagents which have a NHS ester group (amine reactive) and a maleimide group (sulfhydryl reactive) on each end. They can be used for binding proteins that have sulfhydryl groups (such as Fab’) to enzymes such as POD and ALP.
- Homo-bifunctional Reagents contain the same reactive group on both ends of the spacer arm. Dojindo offers reagents that have 2 NHS ester groups. They can be used to bind proximate proteins or to introduce NHS ester group to compounds that have amino groups.
| Application | Products |
| Amine Reactive | Ab-10 Rapid Biotin Labeling Kit Biotin Labeling Kit-NH2 Biotin-OSu Biotin-AC5-OSu Biotin-(AC5)2-OSu Biotin Sulfo-OSu Biotin-AC5 Sulfo-OSu Biotin-(AC5)2 Sulfo-OSu Biotin-SS-Sulfo-OSu |
| Thiol Reactive | Biotin Labeling Kit-SH Biotin-PEAC5-maleimide Biotin-PE-maleimide Biotin-HPDP |
| Aldehyde Reactive | ARP (Aldehyde Reactive Probe) |
| Application | Products |
| Amine Reactive | Ab-10 Peroxidase Labeling Kit Alkaline Phosphatase Labeling Kit-NH2 Peroxidase Labeling Kit-NH2 |
| Thiol Reactive | Alkaline Phosphatase Labeling Kit-SH Peroxidase Labeling Kit-SH |
| Application | Products |
| Homo-Bifunctional Reagents | BS3 DSP DTSSP |
| Hetero-Bifunctional Reagents | EMCS GMBS KMUS Sulfo-EMCS Sulfo-GMBS Sulfo-HMCS Sulfo-KMUS SPDP Sulfo-SMCC Sulfo-AC5-SPDP |
| Application | Products |
| Chelate Labeling | AB-NTA free acid |
| Chelate Labeling of Proteins | DTPA anhydride |
| – | Isothiocyanobenzyl-NTA Isothiocyanobenzyl-EDTA |
| Chelate Labeling of Proteins Surfaces with Sulfhydryl Groups | Maleimido-C3-NTA |
| Application | Products |
| Exosome Membrane Labeling | ExoSparkler Exosome Membrane Labeling Kit – Green ExoSparkler Exosome Membrane Labeling Kit – Red ExoSparkler Exosome Membrane Labeling Kit – Deep Red |
| Exosome Protein Labeling | ExoSparkler Exosome Protein Labeling Kit – Green ExoSparkler Exosome Protein Labeling Kit – Red ExoSparkler Exosome Protein Labeling Kit – Deep Red |