Oxidant-density–defined redox regime transition in APS-mediated hemoglobin oxidation
Inorganic Chemistry Communications, vol.193, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 193
- Publication Date: 2026
- Doi Number: 10.1016/j.inoche.2026.117434
- Journal Name: Inorganic Chemistry Communications
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, DIALNET
- Keywords: Ammonium persulfate, Hemoglobin, Kinetic regime transition, Metalloprotein oxidation, Oxidant density, Radical-mediated redox
- Anadolu University Affiliated: Yes
Abstract
Hemoglobin (Hb) oxidation under radical-generating conditions is commonly interpreted within a single kinetic framework; however, whether oxidant density alters the effective scaling behavior of redox redistribution remains unclear. Here, ammonium persulfate (APS)–mediated Hb oxidation has been quantitatively investigated using an integrated kinetic approach that combines pseudo-first-order modeling, early-phase initial-rate analysis, and a redox flux directionality parameter (ΔR[jls-end-space/]) under microplate UV–Vis conditions.Across the investigated APS range (0–1.0 mg mL−1), oxyhemoglobin (oxyHb) depletion, methemoglobin (metHb) formation, and deoxyhemoglobin (deoxyHb) accumulation exhibited concentration-dependent redistribution. Within the low-APS window (0–0.125 mg mL−1), apparent rate constants and initial formation rates scaled linearly with oxidant concentration, consistent with kinetically controlled radical behavior. In contrast, increasing APS density led to a progressive deviation from linear proportionality across independent kinetic descriptors, indicating a transition in effective scaling behavior.Comparative sensitivity analysis revealed a hierarchical antioxidant response (k2,met>k2,oxy>k2,deoxy[jls-end-space/]), identifying ferric conversion as the dominant early oxidative pathway. Antioxidant intervention further supported this interpretation: ascorbic acid markedly suppressed ferric accumulation, whereas glutathione primarily modulated redox redistribution without fully preventing oxidative flux.These findings establish an oxidant-density–resolved kinetic framework for radical–metalloprotein systems and provide a quantitative basis for distinguishing proportional redox modulation from nonlinear oxidative redistribution as radical load increases.