Influence of pH on radical reactions between kynurenic acid and amino acids tryptophan and tyrosine. Part II. Amino acids within the protein globule of lysozyme.

Abstract in brief

• The study examines how pH levels affect radical reactions between kynurenic acid (KNA) and amino acids tryptophan (Trp) and tyrosine (Tyr) within a model protein, lysozyme, showing that while some reaction rates remain constant, the damage process shifts from crosslinking to oxygenation as pH drops from 7 to 5.
• Results indicate that pH influences the type of protein damage, with lower pH reducing Trp-Trp crosslinking and increasing oxygenation, leading to different modifications at specific Trp and Tyr residues.
• The findings highlight that radical reactions involve both crosslinking and oxygenation processes within proteins and that changes in pH can significantly impact the pathways and extent of protein damage, especially in environments like the eye lens where kynurenic acid is present.]