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Semiautomated enzymic microassay for plasma L-alanine
Enzyme
|January 1, 1979
Summary
This study introduces a new method to measure L-alanine in plasma using bacterial alanine-dehydrogenase and a colorimetric assay. The assay is specific, reproducible, and can determine L-alanine concentrations in small human plasma samples.
Area of Science:
- Biochemistry
- Analytical Chemistry
- Clinical Diagnostics
Background:
- Plasma L-alanine levels are important biomarkers.
- Accurate quantification of L-alanine is crucial for clinical and research purposes.
- Existing methods may have limitations in sensitivity or sample volume.
Purpose of the Study:
- To develop and validate a sensitive microassay for quantifying plasma L-alanine.
- To establish optimal conditions for the assay.
- To determine normal L-alanine concentrations in human plasma.
Main Methods:
- Enzymatic deamination of L-alanine by bacterial alanine-dehydrogenase.
- Removal of liberated ammonia via dialysis.
- Quantification of ammonia using a continuous flow phenol-hypochlorite colorimetric microassay.
- Analysis of analytical qualities including specificity, reproducibility, and detection limit.
Main Results:
- The assay can determine L-alanine concentrations from 10-1,000 mumol/l in a 50-microliter sample.
- Optimal assay conditions were identified.
- The method demonstrated high specificity, good reproducibility, and a detection limit of 6 mumol/l.
- Normal human plasma values (mean ± 2 SD) were found to be 296 ± 166 mumol/l (arterial) and 376 ± 214 mumol/l (venous).
- Rat plasma L-alanine levels were comparable to human values.
Conclusions:
- A reliable and sensitive microassay for plasma L-alanine has been established.
- The assay is suitable for analyzing small sample volumes.
- The determined normal ranges provide valuable reference data for clinical and research applications.