Hydrazide-modified

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). 

Other molecules can be used in this type of assay approach. Hydrazide-modified (strept)avidin, lectins, biocytin, fluorescent probes and other detectable molecules can be used to detect specifically glycoconjugates in biological samples (Wilchek and Bayer, 1987). 

Conjugation of SFB-Modified Alkaline Phosphatase to Bis-Hydrazide-Modified Oligonucleotides... 

Figure 27.17 SFB may be used to create aldehyde groups on enzyme molecules for subsequent conjugation to a 5 -bis-hydrazide-modified oligonucleotide, forming hydrazone bonds.

Jonas U, Shah K, Norvez S, Charych DH. Reversible color switching and unusual solution polymerization of hydrazide-modified diacetylene hpids. J Am Chem Soc 1999 121 4580-4588. 

A very attractive method for glassy surface activation is silanization with reactive silanes. Thus, many research groups use aldehyde-modified silanes [25], epoxy silanes [26], and mercapto-silanes [27,28] for generating reactive surfaces. Commonly applied silanes are shown in Fig. 13. In the case of the aldehyde linkage a 5 -amino or hydrazide-modified [29] single strand... 

Zhi ZL, Powell AK, Turnbull JE (2006) Fabrication of carbohydrate microarrays on gold surfaces direct attachment of noderivatized oligosaccharides to hydrazide-modified self-assembled monolayers. Anal Chem 78 4786-4793... 

Fig. 11 Coupling of aldehyde containing binding partners to hydrazide-modified sensor surface, followed by cyanoborohydride reduction...

Material. Methotrexate-y-hydrazide was prepared by a modified procedure described by Rosowsky (14). Divinyl ether-maleic anhydride copolymer was purchased from Hercules Incorporated (Wilmington, DE) and had an average molecular weight of 11,400. Centriprep-10 concentrators were purchased from Amicon (Danvers, MA). 

Polysaccharides, glycoproteins, and other glycoconjugates therefore may be specifically labeled on their carbohydrate portions by creating aldehyde functionalities and subsequently derivatizing them with another molecule containing an amine or a hydrazide group. This route of derivatization is probably the most common way of modifying carbohydrates. 

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