Catalase Functions and Glycation: Their Central Roles in Oxidative Stress, Metabolic Disorders, and Neurodegeneration

Catalase, a pivotal antioxidant enzyme, plays a central role in converting hydrogen peroxide (H₂O₂) into oxygen and water, thereby safeguarding cells from oxidative damage. In patients with diabetes, obesity, Alzheimer’s disease (AD), and Parkinson’s disease (PD), catalase becomes increasingly susceptible to non-enzymatic glycation, resulting in enzyme inactivation, oxidative stress, and defective mitochondrial function. This review uniquely emphasizes catalase glycation as a converging pathological mechanism that bridges metabolic and neurodegenerative disorders, underscoring its translational significance beyond prior general reviews on catalase function. In patients with metabolic diseases, glycation impairs β-cell function and insulin signaling, while in patients with neurodegeneration, it accelerates protein aggregation, mitochondrial dysfunction, and neuroinflammation. Notably, the colocalization of glycated catalase with amyloid-β and α-synuclein highlights its potential role in protein aggregation and neuronal toxicity, a mechanism not previously addressed. Therapeutically, targeting catalase glycation opens up new avenues for intervention. Natural and synthetic agents can be used to protect catalase activity by modulating glyoxalase activity, heme integrity, or carbonyl stress. Vitamins C and E, along with agents like sulforaphane and resveratrol, exert protection through complementary mechanisms, beyond ROS scavenging. Moreover, novel strategies, including Nrf2 activation and receptor for advanced glycation end products (RAGE) inhibition, are showing promise in restoring catalase activity and halting disease progression. By focusing on glycation-specific mechanisms and proposing targeted therapeutic approaches, this review positions catalase glycation as a novel and clinically relevant molecular target in patients with chronic diseases and a viable candidate for translational research aimed at improving clinical outcomes.