A fluorimetric assay for aminopeptidase W

Area of Science:

• Biochemistry
• Enzymology
• Analytical Chemistry

Background:

• Aminopeptidase W is a key enzyme involved in various physiological processes.
• Accurate quantification of aminopeptidase W activity is crucial for research and diagnostics.
• Existing assays for aminopeptidase W may lack specificity or require complex methodologies.

Purpose of the Study:

• To develop and validate a novel, sensitive, and specific enzyme-linked fluorimetric assay for aminopeptidase W.
• To compare the performance of the new assay with established methods for measuring aminopeptidase W activity.

Main Methods:

• A two-step enzyme-linked assay utilizing L-alpha-Glutamyl-L-tryptophan (Glu-Trp) as the substrate.
• Measurement of released glutamate via an increase in NADH fluorescence using glutamate dehydrogenase (EC 1.4.1.2).
• Validation through comparison with high-performance liquid chromatography (HPLC) and immunoradiometric assays.

Main Results:

• The assay demonstrated high specificity for aminopeptidase W, with minimal interference from other peptidases (e.g., aminopeptidases N and A) using specific inhibitors.
• Cytosolic activities were inhibited by N-ethylmaleimide, while aminopeptidase W activity remained unaffected.
• Excellent correlation was observed between the fluorimetric assay and both HPLC and immunoradiometric methods.

Conclusions:

• The developed fluorimetric assay provides a reliable and specific method for quantifying aminopeptidase W activity.
• This novel assay offers an advantageous alternative for researchers studying aminopeptidase W.
• The assay's specificity and good correlation with other methods support its utility in various biological contexts.