Periodate oxidation labeling

Figure 9.26 AMCA-hydrazide can be used to label aldehyde-containing molecules, such as periodate-oxidized carbohydrates.

The hydrazide derivative of AMCA can be used to modify aldehyde- or ketone-containing molecules, including cytosine residues using the bisulfite activation procedure described in Chapter 27, Section 2.1. AMCA-hydrazide reacts with these target groups to form hydrazone bonds (Figure 9.26). Carbohydrates and glycoconjugates can be labeled specifically at their polysaccharide portion if the required aldehydes are first formed by periodate oxidation or another such method (Chapter 1, Section 4.4). 

AMCA-hydrazide is soluble in DMSO or DMF and may be dissolved as a concentrated stock solution in either of these solvents prior to the addition of a small aliquot to an aqueous reaction medium. The solid and all solutions made from the fluorophore must be protected from light to avoid photo-decomposition. Prepare the stock solution fresh immediately before use. A suggested protocol on the use of this fluorescent probe may be obtained from the following method on the labeling of periodate-oxidized IgG. Optimization may be necessary to achieve the best level of fluorescent modification (F/P ratio) for a particular application. 

Figure 9.48 A cyanine dye containing a hydrazide group can be used to label glycans at their reducing end or other reducing sugars, forming a hydrazone linkage. Glycoproteins also can be labeled after periodate oxidation to form aldehyde groups.

The following protocol describes the use of biotin-hydrazide to label glycosylated proteins at their carbohydrate residues. Control of the periodate oxidation level can result in specific labeling of sialic acid groups or general sugar residues (Chapter 1, Section 4.4). 

In addition to the foregoing examples, periodate oxidation has been applied to isotopically labeled sugars (for the determination of label distribution), 226 -226 to certain branched-chain sugars,227-229 and to some nitrogenous derivatives of the simple sugars.230-236... 

Carbonyl Groups Labeling. This was done under the usual conditions of PATAg staining (periodic acid, thiocarbohydrazide, silver proteinate) reactions (2) omitting the periodate oxidation step (= TAg), as described in... 

Many types of mono-, bi-, and multifunctional coupling reagents are available for labeling antibodies or antigens with an enzyme. Glutaraldehyde, carbodiimide, N-succinimidyl-3-(2-pyridyldithio)propionate, and periodate oxidation of carbohydrate moieties to form active dialdehydes are several commonly used approaches in the preparation of enzyme conjugates (104-106). 

An alternative approach to the synthesis of isocoumarins which probably proceeds through the intermediacy of 2-carboxybenzyl ketones is based on the oxidative cleavage of indan-1-ones (76JCS(P1)1438). Although ozonolysis of the silyl enol ether (505) leads to the 2-hydroxy-2-methylindan-l-one (506), periodate oxidation of which gives the isocoumarin, a more convenient and direct route involves ozonolysis of the enol trifluoroacetate (Scheme 182). This synthesis is especially attractive for the preparation of isotopically labelled isocoumarins, since the precursors of the indanones, arylpropanoic acids or acrylophenones, are readily available bearing labels at specific sites. 

Key Words Antibody horseradish peroxidase conjugation labeling periodate oxidation. 

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