Label reagents

AIBN was synthesized using C-labeled reagents and the tagged compound was used to initiate polymerization of methyl methacrylate and styrene. 

Paquatte, O., Fried, A., and Tu, S. C. (1988). Delineation of bacterial luciferase aldehyde site by bifunctional labeling reagents. Arch. Biochem. 264 392-399. 

Finally, we have also attempted to improve on the fluorescence and chemiluminescence efficiencies of the labeling reagent, the naphthalene dialdehyde. Derivatives 7, 8, and 9 (Table IX) have been synthesized and studied. As shown in Table IX, none of these new derivatives presents an advantage over the parent unsubstituted CBI-Ala. 

Figure 2. The pH dependency of heparin labelling. The degree of labelling intensity of the final product was compared with the concomitantly measured solubility of the F-D labelling reagent.

Maximum labelling of heparin with F-D was achieved at 5 hours at 25 °C, pH 8.4. In the case of heparin, the efficiency of labelling was not dependent on molecular weight, but solely a function of the ratio of the concentrations of labelling reagent to monosaccharide subunit in the reaction mixture. Similar results were encountered in the labelling of dextrans of different molecular weight (9). 

Fluorescent labeling requires care. Unless the protein is completely labeled, which requires heroic effort, incomplete labeling converts each protein into a complex mixture of reaction products. We find that the use of FQ as the labeling reagent and the use of an SDS-containing buffer produces extremely high-efficiency separations of labeled proteins. 

Klinker CC, Bowser MT (2007) 4-Fluoro-7-nitro-2, 1, 3-benzoxadiazole as a fluorogenic labeling reagent for the in vivo analysis of amino acid neurotransmitters using online microdialysis-capillary electrophoresis. Anal Chem 79 8747-8754... 

Mujumdar RB, Ernst LA, Mujumdar SR, Lewis CJ, Waggoner AS (1993) Cyanine dye labeling reagents sulfoindocyanine succinimidyl esters. Bioconjugate Chem 4 105-111... 

Ernst LA, Gupta RK, Mujumdar RB, Waggoner AS (1989) Cyanine dye labeling reagents for sulfhydryl groups. Cytometry 10 3-10... 

Mujumdar SR, Mujumdar RB, Grant CM, Waggoner AS (1996) Cyanine-labeling reagents sulfobenzindocyanine succinimidyl esters. Bioconjugate Chem 7 356-362... 

Nowadays, antibodies are utilized in numerous immunoanalytical methods. Those widely used in practice, such as radioimmunoassays, fluoroimmunoassays and enzyme-linked immunosorbent assays (ELISA), require labelled reagents. Millions of ELISA tests for diagnostics of various diseases are daily performed in clinical laboratories. The detection of analytes by two-antibody "sandwich" ELISA, is schematically outlined in Figure 3. 

There now are available a number of alkyl azide compounds that may be used in click chemistry reactions and the Staudinger ligation processes. It is not recommended, however, to use aryl azide compounds, as these are light sensitive and photoreactive as well as highly susceptible to reduction in the presence of thiols. Unfortunately, at the time of this writing there are fewer choices in aryl phosphine compounds to participate in this reaction, as commercial sources of labeling reagents are limited. 

Bergmann, K.E., Carlson, K.E., and Katzenellenbogen, J.A. (1994) Hexestrol diazirine photo-affinity labeling reagent for the estrogen receptor. Bioconjugate Chem. 5, 141-150. 

Khalfan, H., Abuknesha, R., Rand-Weaver, M., Price, R.G., and Robinson, D. (1986) Aminomethyl cou-marin acetic acid A new fluorescent labeling reagent for proteins. Histochem. /. 18, 497-499. 

Roth, J., Taatjes, D.J., and Warhol, M.J. (1989) Prevention of non-specific interactions of gold-labeled reagents on tissue sections. Histochemistry 92, 47-56. 

Schnapp, K.A., Poe, R., Leyva, E., Soundararajan, N., and Platz, M.S. (1993) Exploratory photochemistry of fluorinated aryl azides. Implications for the design of photoaffinity labeling reagents. Bioconjugate Chem. 4, 172-177. 

Takadate, A., Irikura, M., Suehiro, T., Fujino, H., and Goya, S. (1985) New labeling reagents for alcohols in fluorescence high-performance liquid chromatography. Chem. Pharm. Bull. 33, 1164-1169. 

---