Peptide-carbohydrate hybrid

A series of peptide-carbohydrate hybrid block copolymers, such as dextran-p-PBLG [114], dextran-fi-PS, and hyaluronan-(>-PBLG [115], have been utilized... 

In connection with our longstanding interest on the preparation of carbohydratelike molecules [13-16] as well as the applications of carbohydrates to the synthesis of natural [17,18] and unnatural products [19-21], we have had the opportunity to use unsaturated carbohydrates for the synthesis of peptide-carbohydrate hybrids [22-26], as well as functionalized heterocycles and alkaloids [27-29], and an outline of our recent results is reported herein. 

This last class of peptide-scaffold hybrids (Q) is readily synthesized from the Claisen and Overman rearrangements products. Some examples of peptide-carbohydrate hybrids are shown in Figure 14.5. 

FIGURE 14.5 Examples of peptide-carbohydrate hybrids synthesized in our group. 

REARRANGEMENTS IN CARBOHYDRATE TEMPLATES TO THE WAY TO PEPTIDE-SCAFFOLD HYBRIDS AND FUNCTIONALIZED HETEROCYCLES... 

Chapter 14, by Herraddn and coworkers, describes rearrangements of carbohydrate templates as the pathway to functionalized heterocycles and peptide-scaffold hybrids. 

We use sugar amino add as a fundional, sucdnct classification term, although a plethora of terms have been proposed in the literature for compounds derived from Saa. These include saccharide-peptide hybrids, glycosamino adds, peptidosaccharides, sac-charopeptides, amide-linked carbohydrates, and carbopeptoids, although the latter compounds most often do not have a peptoid functionality. In some cases Saa are linked to each other, in other cases to amino acids. 

Other known oligonucleotide analogs include oligomers in which the heterocyclic bases have been modified [155] or replaced by other types of compound [156], Solid-phase syntheses of hybrids of DNA with peptides [157-163], with carbohydrates [164,165], and with PNA (peptide nucleic acids, see Section 16.4.1.2 [166-168]) have also been reported, and several strategies have been developed that enable the preparation of oligonucleotides with a modified 5 - or 3 -terminus [169-174] or of cyclic oligonucleotides [122,175], Various techniques for the parallel solid-phase synthesis of oligonucleotides have been developed for the preparation of compound libraries [176-181],... 

There are various hybrid 2-D correlation experiments that combine features of two simpler 2-D experiments. A popular and useful example is the HMQC-TOCSY spectrum that correlates one-bond H—13C couplings (HMQC) but shows these correlations throughout an entire spin system (TOCSY). This experiment simplifies complex carbohydrate and peptide systems and allows ready assignments of systems of protons and carbons. 

Glycomimetics Linked sugars Spaced sugars Functional mimetics Saccharide-peptide hybrids Sugar amino acids Solid phase synthesis Sialyl Lewis Carbohydrate medicinal chemistry... 

This type of carbohydrate mimetic was coined saccharide-peptide hybrid to point out that carbohydrate properties as well as peptide properties are represented. The mimetics still retain the carbohydrate epitopes available for binding, the p)ranose or furanose ring plus hydroxy groups, as well as the peptide function. 

Glycoconjugates are those hybrid biochemicals which contain carbohydrate chemically bonded to some other component such as peptide (glycopeptide), protein (glycoprotein), lipid (glycolipid), and others. 

A chip containing both carbohydrates and glycoproteins permits the rapid determination of the context of binding to the glycoprotein. Incubation of proteins with this hybrid array establishes whether the peptide context is essential for binding or the carbohydrate structure alone is sufficient. To prepare these slides, the glass surface is usually modified with two different chemistries, for example, on one side a maleimide chemistry, and on the other an N-hydroxysuccinimide (NHS) activated ester. 

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