Glycoproteins periodate oxidation

Glycoproteins Periodic oxidation followed by treatment with Schiff s reagent Quantitative... 

Glycoproteins Periodate oxidation + treatment with SchlfPs reagent Visual, quantitative... 

Dissolve an aldehyde-containing macromolecule to be modified (i.e., a periodate-oxidized glycoprotein) in 0.01M sodium phosphate, 0.15M NaCl, pH 7.4, containing ImM EDTA. A suitable concentration range for a protein is l-10mg/ml. 

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.

Figure 14.19 Aldehyde-containing molecules, such as periodate-oxidized carbohydrates or glycoproteins, can be coupled to hydrazide-particles to form a hydrazone bond. This bond can be further stabilized by reduction...

The following protocol describes a method for the periodate oxidation of a glycoprotein followed by biotinylation of the resultant aldehydes using hydrazide-PEG4-biotin. Chapter 1, Section 4.6 describes an alternative protocol for the modification of glycans at their reducing ends with hydrazide compounds. 

Periodate Oxidation of Glycoproteins Followed by Reductive Conjugation... 

Hydrazide derivatives also may be prepared from a periodate-oxidized dextran polymer or from a carboxyl-containing dextran derivative by reaction with te-hydrazidc compounds (Chapter 4, Section 8). A hydrazide terminal spacer provides reactivity toward aldehyde- or ketone-containing molecules. Thus, the hydrazide-dextran polymer can be used to conjugate specifically glycoproteins or other polysaccharide-containing molecules after they have been oxidized with periodate to form aldehydes (Chapter 1, Section 4.4). 

Hydrazide groups can react with carbonyl groups to form stable hydrazone linkages. Derivatives of proteins formed from the reaction of their carboxylate side chains with adipic acid dihydrazide (Chapter 4, Section 8.1) and the water-soluble carbodiimide EDC (Chapter 3, Section 1.1) create activated proteins that can covalently bind to formyl residues. Hydrazide-modified enzymes prepared in this manner can bind specifically to aldehyde groups formed by mild periodate oxidation of carbohydrates (Chapter 1, Section 4.4). These reagents can be used in assay systems to detect or measure glycoproteins in cells, tissue sections, or blots (Gershoni et al., 1985). 

The sensitivity to periodate of Ser and Thr is thousands of times greater than that of the better known periodate oxidation of 1,2-cis-diols, for example in the sugars of glycoproteins.19 This means that the concentration of reagent can be kept very low, in only small excess over the l-amino-2-alcohol, and the reaction time kept short (3 to 10 min). It is, thus, usually possible to avoid oxidative attack of the side chains of Met, Trp, and His, but some risk of... 

On the other end of the cross-linker, the hydrazide functional group can react with periodate-oxidized carbohydrate molecules to form hydrazone linkages (Chapter 1, Sections 2 and 4.5). Thus, glycoproteins can be targeted specifically at their polysaccharide chains, avoiding cross-linking at active sites which can lead to activity losses (Fig. 167). 

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