Labeling detection

Selected entries from Methods in Enzymology [vol, page(s)] 2P-labeled [detection, 238, 40, 48, 50-51 disposal, 238, 53 half-life, 238, 40 a-phosphate labeling specificity, 238, 39-40 quality of preparations, 238, 40] regeneration systems, 238, 34-35 stability, 238, 352-354 tritiated [assay advantages, 238, 38 detection, 238, 39, 48, 50-51 disposal, 238, 52-53 half-life, 238, 38 stability of label, 238, 39]. 

After chromatographic removal of 3, the cleavage of the catenane, 4, to 3 and 1 was critical evidence of the structure. Numerous blank experiments excluded other possibilities. Figure 1 essentially describes a double-labeling experiment deuterium for one ring and the acyloin function for the other, the labels detected by their infrared absorption [6], The few milligrams of purified 3 could not be crystallized. The name catenane was based on the Latin catena for chain . 

Y. Zhang and A. Heller, Reduction of the non-specific binding of a target antibody and of its enzyme-labeled detection probe enabling electrochemical immunoassay of an antibody through the 7 pg/mL-100 ng/mL (40 fM-400 pM) range, Anal. Chem., 77 (2005) 7758-7762. 

Metal labels have been proposed to resolve problems connected with enzymes. Metal ions [13-16], metal-containing organic compounds [17,18], metal complexes [19-21], metalloproteins or colloidal metal particles [22-28] have served as labels. Spectrophotometric [22,25], acoustic [25], surface plasmon resonance, infrared [24] and Raman spectroscopic [28] methods, etc. were used. A few papers have been dealing with electrochemical detection. However, electrochemical methods of metal label detection may be viewed as very promising taking into account their high sensitivity, low detection limit, selectivity, simplicity, low cost and the availability of portable instruments. 

Beside different kinds of nanocrystals (or QDs) AuNPs are showing a special interest in several applications. Electrochemical methods used for AuNPs label detection may be very promising taking into account their high sensitivity, low detection limit, selectivity, simplicity, low cost and availability of portable instruments. 

Hirsch, J. D., Eslamizar, L., Filanoski, B. J., Malekzadeh, N., Haugland, R. P., Beechem, J. M., and Haugland, R. P. (2002) Easily reversible desthiobiotin binding to streptavidin, avidin, and other biotin-binding proteins uses for protein labeling, detection and isolation. Anal. Biochem. 308, 343-357. 

Occasionally, a laboratory will need an in-line detector of radio-labeled molecules. These detectors take the flow from the column or from an initial detector, mix it with fluorescing compound, and measure the fluorescence due to radioactive breakdown. A different system uses beads in the flow cell with an immobilized fluorescing compound, but these systems suffer from ghosting and cannot be used with very hot labeled compounds because of secondary radiation problems. These systems are very useful with tritiated samples and less so with carbon14 labeled compounds. Some success has been reported with sulfur32 label detection. 

Ansari B, Coates PJ, Greenstein BD, Hall PA. In situ end-labelling detects DNA strand breaks in apoptosis and other physiological and pathological states. J Pathol 1993 170 1-8. 

Figure 4.12 describes two popular antibody microarrays formats that are constructed for antigen capture in small sample volumes with detection by either sandwich immunoassay or antigen labeling. In sandwich immunoassay, capture antibodies are arrayed and immobilized to select specific proteins which are then found by a second labeled detection antibody. In protein target labeling, all proteins in the sample are prelabeled (i.e., fluorescent dyes) prior to capture by immobilized antibody arrays. In direct assay systems, sample proteins are directly immobilized onto... 

Sensitive, semi-quantitative Sensitive, quantitative High resolution In vivo or in vitro labeling No labeling necessary Bidifferential expression Small sample size Detects PTMs Sensitive, quantitative In vivo or in vitro labeling 4 stable isotope labels Detects PTMs Sensitive, quantitative Cell culture labeling Bidifferential expression Detects PTMs... 

Besides radionuclides (detected on the basis of beta and gamma radiation), labels detected by the measurement of magnetic resonance have been proposed (spin labels - spin immunoanalysis, abr. SIA). Other labels are fluorescent dyes already... 

In double-site immunometric assays (i.e., sandwich assays [29], see Fig. 9.9) the sample containing the analyte is incubated with both a capture antibody, usually immobilized on a solid phase, and a labelled detecting antibody. After the excess of labelled antibody is removed, the measured signal can be correlated directly to the analyte concentration. 

Fig. 9.9. Double-site immunometric assay The sample containing the anedyte is incubated with the capture antibodies immobilized on a solid support (1), until equilibrium (2) is established. Then, labelled detection antibodies (3), recognizing a different epitope on the antigen than capture antibodies, are added onto the support, and the excess of detection antibodies is removed by washing (4). The amount of the label bound to the support is detected (5).

E639 Kissel, T. (1990). Simple combination substrate solution for dual-label detection in heterogeneous enzyme immunoassays. Clin. Chem. 36, 1094, Abstr. 666. 

The purpose of this appendix is to deal with methods for the labeling, detection, and quantitation of viral DNA. Two methods, cRNA-DNA and DNA-DNA hybridization, which have been routinely used in the author s laboratory for assessing the drug efficacy in the EBV system, are discussed. 

For protein microarrays, several label detection techniques are already used because of their simplicity, broad availability of fluorescence dyes and chemical functional groups for conjugation, and scanning instruments. 

---