Novel fluorometric protocol for assessing myeloperoxidase activity.

Area of Science:

• Biochemistry
• Immunology
• Analytical Chemistry

Background:

• Neutrophil myeloperoxidase (MPO) is a key enzyme in the innate immune system.
• Accurate measurement of MPO activity is crucial for understanding neutrophil function in various diseases.
• Existing spectrophotometric and fluorometric methods have limitations.

Purpose of the Study:

• To develop and optimize a novel, sensitive, and accurate fluorometric method for quantifying MPO activity.
• To specifically measure MPO activity based on the hydrogen peroxide (H₂O₂)-dependent oxidation of thiamine.

Main Methods:

• Utilized response surface methodology (RSM) with Box-Behnken Design (BBD) for method optimization.
• Analyzed experimental parameters including H₂O₂ concentration, incubation time, and thiamine concentration.
• Employed analysis of variance (ANOVA) to determine optimal conditions and model significance.

Main Results:

• Optimal conditions determined: 1000 µM H₂O₂, 10 min incubation, 1000 µM thiamine, yielding 30 ± 2 U/L MPO activity.
• The method demonstrated significant accuracy, sensitivity, and linearity up to 60 IU.
• Strong correlation observed between the new fluorometric method and standard colorimetric assays.

Conclusions:

• The developed fluorometric method provides a dependable and efficient means for assessing MPO activity.
• This advanced protocol offers excellent accuracy, sensitivity, and linearity, beneficial for researchers and clinicians.
• The method serves as a valuable tool for investigating neutrophil function and associated diseases.