Analysis of peptides in a sheep beta lactoglobulin hydrolysate as a model to evaluate the effect of peptide amino acid sequence on bioactivity

Abstract

Fungal protease FPII was found to hydrolyse sheep β-lactoglobulin (β-Lg), and the hydrolysate exhibited substantial antioxidant and ACE inhibition bioactivities. From analysis of the peptide sequences in the hydrolysate in relation to bioactivity, synthetic peptides corresponding to four regions of sequence in β-Lg (LAFNPTQLEGQCHV, DTDYKKYLLF, LDAQSAPLRVY and VEELKPTPE) were analysed for bioactivity. Additional synthetic peptides were designed to examine the bioactivity of different parts of the above four sequences, and the effect of amino acid substitutions on bioactivity. The results show that parts of the peptide sequences contribute differently to bioactivity and substitution of amino acids has a substantial effect on antioxidant and ACE inhibition activities.

Keywords: Amino acid substitution; Antioxidant and ACE inhibition bioactivity; Fungal protease FPII hydrolysate; MALDI-TOF; RP-HPLC; Sheep β-lactoglobulin; Synthetic peptides.