# Screening and Identification of Antioxidant Peptides from Sea Cucumber Gonad Proteins and Their Activation of Superoxide Dismutase

## TL;DR

Researchers found four antioxidant peptides from sea cucumber gonads that activate superoxide dismutase, offering potential for functional foods.

## Contribution

Identification of novel antioxidant peptides from sea cucumber gonads with SOD-activation potential.

## Key findings

- Four antioxidant peptides were isolated and shown to scavenge free radicals effectively.
- Peptides formed strong interactions with SOD through molecular docking and simulations.
- NPWGQ was the most potent antioxidant and SOD-activating peptide identified.

## Abstract

The gonad is one of the major byproducts of sea cucumber. Four novel antioxidant peptides (NPWGQ, PGHPF, VPYPR and ATGPQGPAGQRGPAGPTGPTGPAG) were isolated and identified from sea cucumber gonad proteins through enzymatic hydrolysis and antioxidant activity-guided fractionation, bioinformatics approaches and in silico screening. These peptides demonstrated great free radical (2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS))-scavenging activity and notable superoxide dismutase (SOD)-activation capacity. Molecular docking and molecular dynamics simulation data suggested that these peptides could form strong binding with SOD through hydrogen bonding, electrostatic interactions, and hydrophobic interactions. Among these peptides, NPWGQ displayed the most potent antioxidant and SOD-activating effects. Through searching known databases, these peptides did not show potential toxicity and are generally considered safe. The present study provides crucial theoretical support for comprehensively utilizing sea cucumber (Holothuroidea) gonad by-products and generating high-value functional food ingredients or dietary supplements.