Starch scavenges degradation products from protein solutions

The shelf life of proteins in-vitro is limited by their susceptibility to various degradation processes. This study demonstrates that starch can extend protein stability by selectively removing non-proteolytic degradation products. Using NMR spectroscopy, we show that starch effectively scavenges degraded protein impurities while preserving the native protein structure as indicated by nearly identical [¹⁵N, ¹H]-HSQC spectra for fresh intact protein and degraded protein samples treated by starch. The interaction is primarily electrostatic, with starch exhibiting a strong affinity for positively charged amino acids such as arginine, lysine, and histidine. Molecular dynamics simulations further reveal that amylose stabilizes these amino acids through hydrogen bonding and charge-dipole interactions, reducing backbone flexibility. This low-cost, easy-to-implement approach holds promise for improved protein stability and has broad pharmaceutical applications.