Tetrapeptides, synthesis

Meanwhile, back at the tetrapeptide synthesis, methionine (Met) has been BOC-protected, and is ready for activation—as a 2,4,6-trichlorophenyl ester (Cp) this time and coupling with the de-protected Asp-Phe-OMe. Aqueous acid takes off the BOC group without hydrolysing peptide or ester bonds, and a repeat of this cycle with BOC-tryptophan trichlorophenyl ester (BOC-Trp-OCp) finally gives the tetrapeptide. 

Nonpowdery polymer easy to filter can be used in a column, used for synthesis of linear tetrapeptides, and peptide substrate for porcine elastase Tetrapeptide synthesis... 

The sequence of each different peptide or protein is important for understanding the activity of peptides and proteins and for enabling their independent synthesis, since the natural ones may be difficult to obtain in small quantities. To obtain the sequence, the numbers of each type of amino acid are determined by breaking down the protein into its individual amino acids using concentrated acid (hydrolysis). For example, hydrolysis of the tetrapeptide shown in Figure 45.3 would give one unit of glycine, two units of alanine, and one unit of phenylalanine. Of course, information as to which amino acid was linked to which others is lost. 

Merrifield RB. Solid phase peptide synthesis I. The synthesis of a tetrapeptide. J Am Chem Soc 1963 85 2149-2154. 

The synthesis of the octapeptide isoleucine-5-angiotensin Z-Asp(NH2)-Arg(N02)-Val-Tyr-Ile-His-Pro-Phe-OCH3 using CDI as condensing agent was achieved by preparing the four required dipeptides (1—2), (3-4), (5-6), (7-8), two tetrapeptides (1-4) and (5-8), and finally the octapeptide itself. 123... 

Brandi, L., Lazzaroni, A., Cavalletti, L., Abbondi, M., Corti, E., Ciciliato, I., Gastaldo, L., Marazzi, A., Feroggio, M., Maio, A., Colombo, L., Donadio, S., Marinelli, F., Losi, D., Gualerzi, C. O., and Selva, E. (2006c). Novel tetrapeptide inhibitors of bacterial protein synthesis produced by a streptomyces. Biochemistry 43, 3700—3710. 

RD Tung, MJ Dhaon, DH Rich. BOP-C1 mediated synthesis of cyclosporin A 8-11 tetrapeptide fragment. J Org Chem 51, 3350, 1986. 

K. Gademann, M. Ernst, D. Hoyer, D. Seebach, Synthesis and Biological Evaluation of a cyclo-/3-Tetrapeptide as a Somatostatin Analogue , Angew. Chem., Int. Ed. 1999, 38, 1223-1226. 

For the synthesis of a small library of palmitoylated and isoprenylated N-Ras peptides in solution, a modular strategy was adopted, with the tetrapeptide MGLP 38 as a key intermediate. This tetrapeptide allowed further elongation at its C-terminus with lipidated or nonlipidated cysteine methyl esters, as well as the addition of various N-terminally MIC-labeled dipeptides, consisting of different GC lipidated units 39—41... 

Scheme 22 Solid-phase synthesis of the biotinylated, farnesylated tetrapeptide (59) using the Kaiser benzophenone oxime resin.

Solid Phase Peptide Synthesis. 1. The Synthesis of a Tetrapeptide, R. B. Merri-FiELD,/. Am. Chem. Soc. 1963, 85, 2149-2154. 

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