Synthesis of Antioxidant Peptide SCAP1 (Leu-Ala-Asn-Ala-Lys)

Abstract

SCAP1 is a pentapeptide isolated from the hydrolysate of oyster (Saccostrea cucullata), which has antioxidant and anticancer properties. This study aims to find a novel strategy to obtain antioxidant peptide SCAP1 (Leu-Ala-Asn-Ala-Lys) through chemical synthesis. This study reports the first synthesis of SCAP1 through the solid phase peptide synthesis (SPPS) method with Fmoc strategy on 2-chlorotrityl chloride resin. A HATU-HOAt coupling reagent was employed in all amide bond formations and 95% TFA in water was employed to release the desired peptide from the solid support. The crude peptide was purified using successive preparative-RP-MPLC and RP-HPLC to obtain the pure peptide. The synthesized peptide was confirmed by mass spectrometry, showing a correct molecular ion peak at m/z 516.3143 (M+H)+, referring to the desired SCAP1. 1H-NMR spectra of the peptide revealed protons signals consistent to the structure of SCAP1. During the synthesis, the coupling between Ala and Asn(Trt) was not straightforward, which led to a low yield of the final product. The use of Trt-based Asn was not a suitable option, as it could cause aggregation during the synthesis, eventually leading to a poor yield of the final product. SCAP1 was obtained as a white solid with a percent yield of 8.28%.