Branched-chain polymeric polypeptides

Fig. 1. Schematic representation of branched-chain polymeric polypeptides.

For the preparation of multivalent epitope conjugates, branched-chain polymeric polypeptide (SAK) was reacted with chloroacetic acid pentachlorophe-... 

M. Ligeti, G. Mezo, K. Marko, E. Madarasz and F. Hudecz, Conjugation of a cyclic rgd derivative to branched chain polymeric polypeptide Synthesis and biological study of AK-(cyclo[RGDfC])),/. Peyt. Sci., 12,178 (2006). 

Schematic structure of branched chain polymeric polypeptides is shown in Figure 1. Polylysine with free s-amino groups, AK or poly [Lys(SerrDL-Alam)], (SAK) containing a-amino groups and poly[Lys(Omi-DL-Ala d], (OAK) possessing both a- and e-amino groups can be considered as polycations. Side chains of poly [Lys(Glui-DL-Alam)], (EAK) contains glutamic acid at the end of the branches. Therefore this polymer has not only free a-amino, but also free y-carboxyl group in the side chain, consequently this compound has amphoteric character. Acetylation of EAK resulted in a polyanionic derivative poly [Lys(Ac-Glui-DL-Alam)], (Ac-EAK).

The unique advantages of NMR in the analysis of carbohydrate structure are only fully apparent in consideration of points 3 and 4. In contrast to the unbranched polymeric nature of polypeptide and nucleic acid chains, carbohydrates may be branched structures, capable of substitution at several points. The monosaccharide constituents are polymerized in nature by a non-template directed, enzymatic process the resulting oligosaccharides are often heterogeneous, differing in detail from a consensus structure. NMR is particularly efficient at investigating the solution conformations, and the dynamic properties of such molecules. 

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