Molecular Structure and Properties Core Components:

• Single polypeptide chain
• Covalently attached heme group
• Iron prosthetic center
• Molecular weight of ~12.4 kDa

Structural Features:

• Type c heme with covalent thioether bonds
• Iron coordination with His18 and Met80
• Reversible Fe²⁺/Fe³⁺ redox states
• α-helical rich structure
• Highly stable tertiary fold
• Surface lysine residues
• Evolutionarily conserved

Cellular Functions and Mechanisms Primary Functions:

• Electron Transport Chain:
• Electron carrier between Complex III and IV
• Reduction-oxidation cycling
• ATP synthesis facilitation
• Energy metabolism regulation
• Apoptotic Signalling:
• Mitochondrial release
• Apoptosome formation
• Caspase activation cascade
• Cell death regulation

Cellular Localization:

• Mitochondrial intermembrane space
• Cytosolic presence during apoptosis
• Nuclear translocation
• Membrane association capabilities

Physiological Roles and Regulation Energy Metabolism:

• Oxidative phosphorylation efficiency
• Proton gradient maintenance
• ATP production regulation
• Metabolic rate control

Redox Homeostasis:

• Oxidative stress response
• ROS management
• Cellular redox state maintenance
• Antioxidant properties

Cell Death Pathways:

• Intrinsic Apoptosis
• Alternative Death Pathways
• Cardiolipin oxidation
• ER stress response

Pathological Implications Disease Associations:

• Cancer:
• Altered expression patterns
• Resistance to apoptosis
• Metabolic reprogramming
• Neurodegenerative Disorders:
• Mitochondrial dysfunction
• Oxidative stress
• Neuronal death
• Cardiovascular Diseases:
• Ischemia-reperfusion injury
• Cardiomyocyte death
• Heart failure progression

Clinical Applications:

• Diagnostic markers
• Therapeutic targets
• Treatment monitoring
• Prognostic indication

Current Research and Future Perspectives Emerging Research Areas:

• Post-translational modifications
• Novel functions
• Non-canonical pathways
• Tissue-specific roles

Therapeutic Development:

• Drug design approaches
• Clinical applications
• Biomarker development
• Treatment monitoring
• Personalized medicine
• Drug resistance assessment