Label-Free Arginase Assays

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Arginase catalyzes the hydrolysis of L-arginine to L-ornithine and urea. Ornithine serves as the biosynthetic precursor of proline, a critical component of collagen and polyamines, which contribute to cell growth and proliferation. Arginase activity also plays a role in the regulation of nitric oxide (NO) synthesis. The upregulation of arginase activity is implicated in various pathologies including cardiovascular diseases such as hypertension, erectile dysfunction, diabetes, and obesity, as well as asthma and tumor immune escape. Thus, arginase modulators could have widespread therapeutic value and are currently targeted for drug discovery.

What We Offer

SAMDI Tech offers the only label-free high-throughput assay for quantitative analysis of arginase activity using native substrates. Our proprietary technology enables the capture and enrichment of the arginine substrate and ornithine product onto SAMDI 384 or 1536 biochip arrays for analysis by mass spectrometry. The label-free platform overcomes the need for cumbersome uorescent-based substrates or indirect readouts that interfere with activity and produce high rates of false-positive hits.

SAMDI Advantages

  • Fast - Eliminates labels and reduces assay development time
  • Efficient - Multi-analyte detection and 10,000s of samples analyzed per day
  • Quantitative - Measures enzyme kinetics, mechanism of action, and IC50s

Assay Format
Current arginase assays require multi-step reactions to functionalize the urea side product, providing an indirect measurement of arginase activity, and are thus susceptible to high rates of false-positive hits. SAMDI mass spectrometry enables the direct detection of the ornithine product.

SAMDI Mass Spectrometry
SAMDI mass spectrum of an arginase reaction shows a loss of 42 m/z, corresponding to the hydrolysis of arginine to ornithine. In this spectrum, approximately 30% of substrate (arginine) is converted to product (ornithine).

Assay Development
SAMDI is quantitative and can report on enzyme kinetics including: Vo vs [Enzyme], enzyme linearity, KM determination, plate uniformity, and IC50 analysis.