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PhosphoSens® Kinase Activity Assays

PhosphoSens assays directly quantify the enzymatic activity of your target by reporting substrate phosphorylation throughout the entire reaction.

Every well delivers a complete activity profile — not just a snapshot. Make faster, smarter discovery decisions with real-time functional data that reveal kinetic behavior and inhibitor dynamics with clarity.

Products & Pricing

Validated Kinase Activity Assays For 500+ Targets

AssayQuant’s biochemical kinase assay products and reagents let you generate real-time activity data across every stage of drug discovery — from screening to hit confirmation and lead optimization. PhosphoSens assays are non-radioactive, antibody-free, and built on a simple, add-and-read homogeneous workflow that directly measures kinase activity with clarity.

Getting Started is Simple

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Explore Product Configurations
Use the selector below to see what comes with each product.
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②
Browse Assay Catalog
Find your protein kinase target in our catalog.
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③
Match & Configure
Match the PhosphoSens Substrate with your target.
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Request a Quote
Let us know the configuration you need.

Product Configurations

What’s included

PhosphoSens
Substrate
PhosphoSens substrate vial
Supplied as a 1 mM stock. Added to the reaction mixture and produces a fluorescent signal proportional to the level of phosphorylation.
ATP
Solution
ATP solution vial
Supplied as a 100 mM stock solution. Phosphate donor that drives the kinase reaction forward, enabling substrate phosphorylation.
EGTA
Solution
EGTA solution vial
Supplied as a 550 mM stock solution. Calcium chelator that helps control divalent cation concentrations for optimal assay conditions.
DTT
Solution
DTT solution vial
Supplied as 1 M stock solution. DTT maintains proteins in a reduced state, preventing disulfide bond formation during assays.
Reaction
Buffer
Reaction buffer vial
Supplied as a 10X stock solution. Description: 500 mM HEPES, pH 7.5, 0.1% Brij-35, 100 mM MgCl2.
Dilution
Buffer
Dilution buffer vial
Supplied as a 5X stock solution. Description: 20 mM HEPES, pH 7.5, 0.01% Brij-35, 5% Glycerol, 1 mg/mL BSA
Recombinant
Enzyme
Recombinant enzyme vial
Supplied as 10 µg of purified kinase protein, ready to drive phosphorylation of the PhosphoSens substrate.
Overview

A Direct, Continuous Fluorescence System for Measuring Kinase Activity and Inhibition

PhosphoSens® Kinase Activity Assays use proprietary peptide substrates that generate a continuous fluorescence signal as they are phosphorylated by recombinant kinases. Unlike endpoint methods that provide only a single measurement, PhosphoSens® delivers true enzymatic activity at the substrate level in real time — no secondary detection or indirect coupling required. Every well produces a complete progress curve that reveals how fast a kinase is working, how strongly an inhibitor reduces activity, and how compounds differ in potency and mechanism of action.

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Designed to meet the needs of modern discovery programs, PhosphoSens assays combine comprehensive kinase coverage with compatibility at physiological ATP concentrations and a simple, homogeneous add-and-read workflow.

Available in flexible formats — from evaluation kits to bulk substrates and supporting reagents — these tools provide reproducible, high-quality data for hit validation, IC₅₀ determination, selectivity profiling, SAR optimization, and lead development.

With PhosphoSens, every well delivers richer insights, helping you make faster, more confident decisions at every stage of discovery.

Not sure where to start?

Talk to a scientist and we’ll help you design the assay and recommend the right products for your targets.

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INTRODUCTORY OFFER

The Best Solutions Start with a Conversation

Not sure which product or service is the best fit for your project? At AssayQuant, our team of scientific experts can provide the guidance and support you need to achieve your research goals.

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How It Works

Assay Principle & Workflow

PhosphoSens assays leverages AssayQuant’s Proprietary Detection Technology to provide real-time, continuous measurements of kinase activity by directly detecting substrate phosphorylation throughout the kinase reaction.

Sensor Peptide Substrates are developed with the Sox readout molecule, covalently attached via a cysteine residue in close proximity to the phosphorylation site (± 2-5 residues). 

As the kinase acts on the substrate, phosphorylation induces a chelation‑enhanced fluorescence (ChEF) signal proportional to phosphorylation level.

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STEP 1

Add

Active enzyme is added to reaction mix containing a Sensor Peptide Substrate, catalyzing phosphotransfer from ATP to the substrate in real time.

STEP 2

Read

Add plate to reader and monitor kinase activity throughout the reaction. Signal is directly proportional to the phosphorylation level of the substrate. 

Screening compound libraries? Struggling with compound autofluorescence?

PhosphoSens-Red Assays offer a time-resolved fluorescence (TRF) readout designed specifically for screening compound libraries. Capture a clear, interference-free signal with a simple, one-time read — using the same assay conditions as our Kinetic format.

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Features & Benefits

Revolutionizing Kinase Research and Drug Development with Continuous Activity Assays

Continuous, Real-Time Monitoring

Captures the entire kinetic profile from start to finish. This approach yields the actual reaction rate, with high accuracy, precision, and confidence.

Direct Measurement of Enzyme Activity

Measures enzyme activity at the substrate level, avoiding the complications of indirect assays that require additional steps.

Physiologically Relevant Conditions

Use biologically relevant peptide substrate sequences in assays that are compatible with low to physiological [mM] concentrations of ATP.

Add & Read Workflow

Achieve fast and reproducible results with a homogenous, single-step workflow without compromising data quality.

SHOP BY TARGET

Browse Our Catalog Of 500+ Protein Kinase Activity Assays To Find The Right PhosphoSens Products For Your Experiments

EXPLORE KINASE ACTIVITY ASSAYS CATALOG

PhosphoSens Kinase Assays Catalog

For your convenience, you can also download a PDF version to review later or share with your colleagues.

Download
Resources & Protocols

Understand How Our Technology Can Support Your Next Discovery

WEBINAR

Deep Kinetic Characterization: When IC50 Isn't Enough

A continuous assay, like our PhosphoSens assay, that measures the catalytic event of phosphorylation in real time enables determination of kinetic parameters that power your drug discovery research.

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BLOG

Continuous vs. Endpoint Kinase Assays: What You Need to Know

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PROTOCOL

PhosphoSens-Kinetic Kinase Inhibitor IC50 Determination 

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