Bioactive sequence

This is traditionally justified since it removes the bulky fluorescent dye from the bioactive sequence. Nonacidic cleavage conditions in the release of targeted peptide from the resin is also a strategy when FTIC is used in solid phase peptide synthesis. 

Bioactive sequences of up to six amino acid residues known to assume (1- or "/-turns in the bioactive conformation are suitable for such libraries. If the sequence is short, residues have to be added in a manner to retain the desired physicochemical properties of the peptide (e.g., to short polar active sequences hydrophobic residues are preferentially added and vice versa). The choice of the scaffold depends on the number of structure-inducing amino acids such as Gly or Pro present in the native sequence. In absence of such residues scaffolds (1) or (4) (Scheme 24) are selected, whereas if Gly or Pro is present alternative scaffolds can be considered. Then the components of the four stereoisomeric sublibraries of Scheme 26 (or their equivalents if other scaffolds are chosen) are synthesized according to procedures described in the preceding sections. 

The proteolytic activation of bioactive sequences by lactic acid bacteria has been debated recently due to the great advantage of using food-grade microorganisms to enrich foods with bioactive substances (Gobbetti et al.,... 

Random polypeptides have traditionally been synthesized by copolymerization of amino acid NCAs. Methods for the synthesis and application of random copolymers have been extensively reviewed (e.g., ref1221), and thus only a single example is given here. A second class of random polypeptides includes organized polymeric assemblies that incorporate bioactive sequences and/or structures. Such polymers have been developed for modulation of protein-ligand interactions/231 protein adsorption to surfaces/241 and cell adhesion/25-281 Several examples for the synthesis of these polymeric assemblies are provided below. 

Studies in recent years have revealed a number of remarkable drug interactions with irreversible or mechanism-based inhibitors of CYP3A, many of which can be attributed to inhibition of sequential intestinal and hepatic first-pass metabolism. Mechanism-based inhibition involves the metabolism of an inhibitor to a reactive metabolite, which either forms a slowly reversible metabolic-intermediate (MI) complex with the heme moiety or inactivates the enzyme irreversibly via covalent binding to the enzyme catalyzing the last step in the bioactivation sequence. As a result, mechanism-based inhibition is both... 

The biological methods of preparation of peptide libraries were introduced by three different groups in 1990 [4-6], These methods, which are also based on combinatorial principles, can be used to prepare even billions of peptide sequences. These sequences appear attached to the end of protein chains. Only the natural L-amino acids can be used as monomers in composition of the libraries. Very effective screening methods are also developed to determine potential bioactive sequences. 

The principle of the method is outlined in Figure 2.5, demonstrating a simple example for determination of a bioactive sequence in three stages. First,... 

The involvement of milk protein-derived cytomodulatory peptides to determine the viability of cancer cells is a field of great interest. Commercial yoghurt starter cultures hydrolyse casein to produce bioactive peptides that control colon cell kinetics in vitro. Bioactive sequences of casein modulate cell viability in different human cell cultures. Peptides from an extract of Gouda cheese inhibited growth of leukemia cells even at 1 pmol/L [223]. They were able to induce apoptosis in the tumor cells. Cancer cells are more reactive to peptide-induced apoptosis than non-malignant cells [224]. Casein-derived peptides could have a role in the prevention of colon cancer by blocking proliferation of the epithelium and by... 

Biosynthetic hydrogels are synthetic systems with binding motifs copied from nature and allow exact control over the chemical structure. Therefore, designed supramolecular hydrogelators can be chemically modified to alter the mechanical properties and to include bioactive sequences. 

Fig. 20 Chemical structure of self-assembling peptide-amphiphile (PA) with bioactive sequence (designed by Stupp et al.)...

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