[Effect of chemical modification on thermal stability of horseradish peroxidase].
Authors: Ugarova, Brovko, Rozhkova, Berezin
Journal: Biokhimiia (Moscow, Russia)
Summary
# Editorial Summary: Chemical Modification and Thermal Stability of Horseradish Peroxidase Chemical modification of horseradish peroxidase's amino groups using glutaric aldehyde, maleic anhydride, and albumin conjugation produced markedly different effects on the enzyme's thermal resilience across the 56–80°C temperature range. Whilst glutaric aldehyde modification compromised both enzymatic activity and stability (reducing thermostability 2.5-fold at 56°C), the maleic anhydride and albumin modifications substantially enhanced thermal resistance, with some preparations demonstrating 25–90-fold greater stability than native enzyme at 56°C. Thermodynamic analysis revealed a strong compensation effect between activation enthalpy and entropy during irreversible thermal inactivation, with both parameters shifting 1.5–2 times whilst free activation energy changed only 2–3 kcal/mol, suggesting the modification alters enzyme structure in ways that redistribute thermal stress rather than fundamentally changing deactivation kinetics. For equine practitioners, this research implies that enzymatic supplements or topical preparations containing horseradish peroxidase could be chemically stabilised to withstand variable environmental and body temperatures without losing efficacy—particularly relevant for wound-healing protocols or joint therapies requiring temperature-resistant bioactive compounds. The selective advantage of albumin conjugation over other modification methods warrants further investigation for veterinary pharmaceutical applications.
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Practical Takeaways
- •Not applicable to equine practice — this is fundamental biochemistry research on enzyme modification with no direct clinical application
Key Findings
- •Chemical modification of horseradish peroxidase with maleic anhydride and inert proteins increased thermal stability 25-90 fold at 56°C compared to native enzyme
- •Glutaric aldehyde modification decreased both enzyme activity and thermal stability by 2.5-fold at 56°C
- •Thermodynamic analysis revealed strong compensation effect between activation enthalpy and entropy (1.5-2 fold changes) while free activation energy changed only 2-3 kcal/mol