Peptide synthesis conventional methods

Another possibility of generating C-terminal azaglycine amides is given by coupling the C-terminal amino acid of a peptide chain with semicarbazide by the conventional methods of peptide synthesis.142 ... 

The purpose of this review was to show the variety of peptides synthesized or isolated from natural products in the last 15 years and to classify the biologically active peptides into the various categories, according to how and where they are formed, their transport, and their general cellular activity. The number of biologically active peptides has risen sharply in the last few years owing to the improvement in the preparative methods in conventional peptide synthesis — at present about 130 different coupling methods are known — and in the solid-phase peptide synthesis. 

Since catalytic asymmetric hydrogenation can generate either or R configuration at the position of the dehydroamino acid residue, this method could be potentially useful for the specific labeling of certain amino acid residues in a polypeptide. The regiospecific and stereoselective labeling of an amino acid residue is difficult to achieve with the conventional stepwise peptide synthesis. We carried out the dideuteration of Ac-APhe-( )Ala-OMe with the use of the cationic rhodium complexes with (-)BPPM and (+)BPPM (Scheme 1), which gave Ac- (R,R)Phe (d ) - (S)Ala-OMe [(R,Rf )/... 

Current practice of the conventional solid phase peptide synthesis (the Merrifield method) is based largely on the use of polystyrene and poly-dimethylacrylamide supports (see Fig. 17). The latter polymer was introduced in the 1970s [12,133 to provide a relatively more polar support, as compared with polystyrene. However, accumulation of experimental evidoice since then (ct Rrf. 70), indicates that an ideal polyn r support for SPPS should be comi tible with both polar (H-bonding) and nonpolar (hydrophobic) residues on the peptic grafts (Fig. 17). When the polymer support is not compatible with the growing peptide grafts, phase separation occurs, and the synthesis becomes inefficient or impracticable. 

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