Reactive species driven oxidative modifications of peptides—Tracing physical plasma liquid chemistry

The effluence of physical plasma consists a significant share reactive species, which may interact with biomolecules and yield chemical modifications comparable to those physiological processes, e.g., post-translational protein (oxPTMs). Consequentially, the aim this work is understand role plasma-derived species in introduction oxPTM-like proteins. An artificial peptide library consisting ten peptides was screened against impact two sources, argon-driven MHz-jet kINPen helium-driven RF-jet COST-Jet. Changes molecular structure were analyzed by liquid chromatography–mass spectrometry. amino acids cysteine, methionine, tyrosine, tryptophan identified as major targets. one, two, or three oxygen atoms most common modification observed. Distinct patterns observed for nitration (+N + 2O–H), occurred only (peroxynitrite), chlorination (+Cl–H) that exclusive COST-Jet presence chloride ions (atomic oxygen/hypochlorite). Predominantly kINPen, singlet oxygen-related modifications, cleavage tryptophan, Oxidation, carbonylation, double oxidations attributed hydroxyl radicals atomic oxygen. Leading change side chain, these affect secondary acid chains, polarity/functionality, ultimately modifying performance stability cellular