Question

Show how you would synthesize Leu-Gly-Ala-Val-Phe starting with Fmoc-Ala-Val-Phe— P

Short answer

The synthesis of Leu-Gly-Ala-Val-Phe starting from Fmoc-Ala-Val-Phe-P is given as follows:

Step-by-step solution

Step-1. Role of Fmoc and DCC in peptide synthesis:

The fluorenylmethyloxycarbonyl protecting group (Fmoc) is a base-labile protecting group used in organic synthesis. It is frequently used as a protecting group for amines, and it is rapidly removed by primary bases as well as secondary bases. Piperidine is usually preferred for Fmoc group removal as it forms a stable adduct. Fmoc protection has found significant use in solid phase peptide synthesis because its removal with piperidine solution does not disturb the acid labile linker between the peptide and the resin.

Dicyclohexylcarbodiimide (DCC) is used as a coupling reagent and its primary role is to couple amino acids during peptide synthesis. The low melting point of this material allows it to be melted for easy handling.

Step-2. Synthesis of Leu-Gly-Ala-Val-Phe from Fmoc-Ala-Val-Phe-Polymer:

The synthesis of Leu-Gly-Ala-Val-Phe from Fmoc-Ala-Val-Phe-Polymer involves the removal of Fmoc protecting group in the first step by deprotecting agent that is, piperidine in DMF. Then, further on reaction with DCC and Fmoc-glycine, coupling reaction takes place and glycine with Fmoc group gets added to the peptide chain from N-terminal end. The, again deprotection of Fmoc group is carried out with piperidine and DMF.

Then, Fmoc protected leucine gets introduced and with the help of DCC, coupling reaction occurs in which Leucine with Fmoc gets added to the growing peptide chain. Finally, after reaction with hydrogen fluoride which is a deprotecting agent, polymer and Fmoc group gets removed and we get required peptide.

Synthesis of Leu-Gly-Ala-Val-Phe