Empower Your Research and Drug Discovery With Kinetic Data Using AssayQuant's PhosphoSens Continuous Assay Format

PhosphoSens® Technology is a continuous assay capturing the entire kinase/phosphatase catalytic reaction enabling superior quantification of inhibitor kinetics in real-time with a straightforward add-and-read workflow and a standard fluorescent plate reader. Our novel and non-disruptive PhosphoSens continuous format provides a data rich progress curve in every well.

WATCH NOW: The Top 3 Reasons A Progress Curve in Every Well Empowers Your Research

Join Dr. Earl May as he highlights some of the most critical reasons why having a progress curve in every well, afforded by a continuous assay format, can be the most impactful to your research.


Earl May, Ph.D., Senior Director of Discovery Technologies

Earl has 25+ years of expertise in drug discovery and enzymology from GSK, OSI and several other biotechnology companies. He has used our Sox sensor peptide technology at all companies he had kinase inhibitor programs, with both reversible and covalent compounds.

"Greater Confidence in Your Readings"

  • In defining the linear portion of a progress curve, an end-point assay requires approximation while a continuous assay provides actual determination.
  • Report the initial rate directly, with higher precision, by measuring catalytic activity throughout the entire kinase reaction.
  • A continuous format provides actionable data by revealing linearity or non-linearity in your progress curve. 

Are you confident you have a straight line?


"Easily Identify & Characterize Progress Curve Lag"

  • A continuous format enables identification and characterization of progress curve lags, which are missed in an end-point format.
  • Reasons for progress curve lags include: experimental design (temperature, mixing, etc.), enzyme activation/autophosphorylation, and (most interestingly) from compound specific dependencies.
  • Avoid missing lags and underestimating rates with a continuous format.

Are you underestimating your rates?


"Recognize & Diagnose Progress Curve Saturation"

  • Saturation can be due to substrate depletion, enzyme instability, product inhibition, or (most interestingly) time-dependent inhibition (TDI).
  • Avoid reporting misleading information (such as an IC50 for an irreversible inhibitor) by accurately uncovering TDI.
  • By yielding a progress curve in every well, our continuous format enables quantification of TDI such as residence time for reversible inhibitors and kinact/KI for irreversible inhibitors.

Can you immediately identify saturation?


Technical Advantages of PhosphoSens Technology:


The PhosphoSens assay captures the entire reaction in real-time enabling determination of kinetic parameters and detailed characterization of inhibition.


Sox fluorophore detects actual phosphorylation and dephosphorylation rather than detecting a proxy such as a binding event or ADP.


PhosphoSens sensor peptides are optimized to bind to the substrate binding site enabling measurement of the true and complete catalytic process.


The PhosphoSens assay is compatible with any ATP concentration - ATP Km for affinity and selectivity independent of compound MOI, and physiological ATP (1-2mM) for continuity with cell-based assays.

  Physiologically Relevant

PhosphoSens sensor peptides are derived from and optimized for interaction with its target kinase or phosphatase.

  Novel and Non-disruptive

PhosphoSens is novel in its delivery of rich information in every well while being non-disruptive in workflow (simple add-and-read format) and equipment (standard fluorescence microplate reader).

Kinome Profiling for Compound Selectivity Progress Curve Analysis for Time-Dependent Inhibition MOI/MOA for Inhibitor-Substrate Competition Studies Red-Shifted End-Point HTS

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