Introduction

• Member of glutathione peroxidase family
• Selenium-dependent enzyme
• Primary functions:
• Breaks down hydrogen peroxide
• Neutralizes organic hydroperoxides
• Counteracts reactive oxygen species (ROS)
• Essential for maintaining bodily homeostasis

Structure and Function Physical Characteristics:

• Located in extracellular space
• Dimeric structure
• Contains selenocysteine residues
• Uses glutathione (GSH) as substrate

Key Functions:

• Protects against oxidative stress
• Guards tissues from:
• Free radicals
• Inflammation
• Metabolic processes
• Converts peroxides to water/alcohol
• Manages ROS signalling pathways

Role in Disease Oxidative Stress and Inflammation:

• Disrupted activity linked to various diseases:
• Heart diseases
• Diabetes
• Neurodegenerative conditions
• Low activity leads to:
• Increased ROS levels
• Tissue damage
• Disease progression
• Protects blood vessels
• Prevents endothelial dysfunction
• Guards against atherosclerosis

Cancer:

• Complex relationship
• Protective role against oxidative stress
• Paradoxical effects:
• Can protect against tumorigenesis
• May promote tumor survival
• Associated with chemotherapy resistance
• Can enhance tumor growth

Regulation and Expression Influencing Factors:

• Dietary selenium levels
• Oxidative stress levels
• Transcription factors

Regulatory Mechanisms:

• Selenium-dependent protein synthesis
• Nrf2 transcription factor activation
• Stress-responsive pathways
• Antioxidant gene regulation