A radiometric microbiologic assay for the biologically active forms at niacin

Area of Science:

• Biochemistry
• Microbiology
• Analytical Chemistry

Background:

• Niacin (Vitamin B3) is essential for human health.
• Accurate measurement of niacin in biological fluids is crucial for clinical diagnostics.
• Existing assays may have limitations in specificity or efficiency.

Purpose of the Study:

• To develop and validate a novel radiometric microbiologic assay for determining niacin levels in biological fluids.
• To assess the specificity and accuracy of the new assay for biologically active niacin forms in humans.

Main Methods:

• Utilized Lactobacillus plantarum to produce 14CO2 from L-[U-14C] hr malic acid, with production proportional to niacin concentration.
• Applied the assay to analyze niacin levels in hemolysates from 30 normal individuals.
• Evaluated assay recovery, reproducibility, and correlation with a conventional turbidimetric method.

Main Results:

• The radiometric assay demonstrated a linear response to niacin concentration.
• Niacin levels in normal hemolysates ranged from 13.0 to 17.8 micrograms/ml RBC (mean = 15.27 +/- 1.33 s.d.).
• Excellent correlation was observed between the radiometric assay and the turbidimetric assay on 30 blood samples.

Conclusions:

• A reliable radiometric microbiologic assay for niacin determination in biological fluids has been established.
• The assay is specific for biologically active niacin forms relevant to human metabolism.
• The developed assay offers a valid alternative to conventional methods for niacin quantification.