Peptide connection

Hunter and Waltho have examined disulfide exchange in peptidic DCLs directed towards binding of the calcium transducer calmodulin (CaM) [23]. The DCL was based upon a known binding motif for CaM consisting of two hydrophobic peptides connected by a flexible linker—ideally suited to a DCC investigation. The library components are shown in Fig. 2.10, and consist of cystine dimers containing hydrophobic amino acid residues. 

Rao and Tam[19 reported the connection of a 24-residue peptide to a small, lysine-based dendrimer (Scheme 7.3). The peptide connection was effected via treatment of the octameric, glyoxylyl-terminated dendrimer 15 with the 1,2-aminothiol polypeptide 16 to afford the thiazolidinyl peptide dendrimer 17. The thiazolidine linkage also introduces a new asymmetric center. 

Insulin is synthesized as proinsulin. After synthesis and folding, a section of the molecule (the C peptide) is excised, leaving the A and B peptides connected via disulfide bridges. Thus, native insulin, lacking the C peptide, lacks some of the information necessary to direct the folding process. 

Cortical bone, 3 Cows, dietary fiber and, 143-144 Cow s milk, ailar gy to, 136 Coxsackievirus, selenium and, 830-831 C>peptide (connecting poplide), 42,167-168 CRABP (cytoplasmic rcHriode acid-binding protein), 560... 

It was emphasized (Kuhn 2004) that, in selecting peptides for use as internal standards, their hydropho-bicity, number of amino acid residues, peptide location within the protein sequence and lack of sites that could be subject to potential post-translational modification should be considered in addition to a high degree of uniqueness in the protein-peptide connectivity (Section 11.6.1). Although multiple MRM transitions were not required (Kuhn 2004) to obtain data of good accuracy and precision for more abundant target proteins, use of relative intensities of more than one (up to five) MRM signals increased the specificity of detection for peptides derived from low abundant proteins in complex proteomics mixtures and thus also increased the confidence of protein identification. 

Fig. 2.1 Peptidocalixarenes calixarenes modified at upper rims with peptides connected through (a) the W-terminus (b) the C-terminus...

Fig. 2.5 (a, c) Peptidocalixarenes and peptidoresoicinatenes with peptides connected at the lower rim (b) lowest energy conformations for 12b and 13b (Reprinted with permission from [23], Copyright 2009 American Chemical Society)... 

---