SPR screening of metal chelating peptides in a hydrolysate for their antioxidant properties

- Metal chelating peptides were screened in protein hydrolysates using SPR.
- An apparent affinity constant and a maximal resonance can be determined with SPR.
- KA should represent the proportion of metal binding peptides in the hydrolysate.
- A correlation was established between SPR-determined KA and metal chelation tests.

There is a growing need in the industrial sector (health, nutrition and cosmetic) to discover new biomolecules with various physico-chemical and bioactive properties. Various beneficial effects of peptides - notably those produced from protein hydrolysis - are reported in the literature. The antioxidant activity involves various mechanisms, among them metal chelation, studied by UV-visible spectrophotometry. In this paper, we set up an original method of screening metal chelating peptides in a hydrolysate using Surface Plasmon Resonance (SPR) for their antioxidant properties. To date, the empirical approach used several cycles of hydrolysate fractionation and bioactivity evaluation until the isolation of the pure bioactive molecule and its identification. Besides, the detection of metal-chelating peptide is not sensitive enough by spectrophotometry. For the first time, metal chelating peptides were screened in hydrolysates using SPR and a correlation was established between affinity constant determined in SPR and metal chelation capacity determined from UV-visible spectrophotometry.