PhosphoSens® Lysate Kinase Activity Assays
PhosphoSens Lysate Assays directly quantify functional kinase activity in cell and tissue lysates. Unlike phosphoprotein methods that only measure phosphorylation state as a proxy, PhosphoSens captures true enzymatic activity at the substrate level, delivering real-time progress curves in a biologically relevant context.
Every well produces a complete activity profile — not just a snapshot — so you can clearly see kinase function, inhibitor dynamics, and pathway modulation in the context of native biology.
Quantify Endogenous Kinase Activity and Signaling in Cell Lysates and Tissue Homogenates - No Antibodies, No Washes, Just a Continuous Signal
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Flexible Configurations Built Around Our Substrates For Your Applications
Cell Lysate Assay Kit (100 Assays)
AQTxxxx-KL-100
$495
Designed for streamlined technology evaluation, each kit includes sufficient volumes of substrate, reaction reagents, cell extraction reagents and controls to perform 100 reactions at 15 μM substrate in a 384-well plate (25 μL reaction volume).
Includes:
- PhosphoSens Kinase-Selective Lysate Substrate
- ATP, EGTA, DTT, Enzyme Reaction Buffer and Enzyme Dilution Buffer
- PhosphoPreserve Cell Extraction Buffer, Protease Inhibitor and Phosphatase Inhibitor Cocktails
- PhosphoControl Peptide, Recombinant Enzyme, Cell Lysate and Reference Compound
Cell Lysate Assay Kit (1,000 Assays)
AQTxxxx-KL-1000
$3,195
Designed for streamlined technology evaluation, each kit includes sufficient volumes of substrate, reaction reagents and cell extraction reagents to perform 1,000 reactions at 15 μM substrate in a 384-well plate (25 μL reaction volume).
Includes:
- PhosphoSens Kinase-Selective Lysate Substrate
- ATP, EGTA, DTT, Enzyme Reaction Buffer and Enzyme Dilution Buffer
- PhosphoPreserve Cell Extraction Buffer, Protease Inhibitor and Phosphatase Inhibitor Cocktails
Kinase-Selective Lysate Substrate (1mg)
AQTxxxx-L-01
$3,500
AssayQuant's Cell Lysate Kinase Assays combine PhosphoSens Detection Technology with high-throughput peptide synthesis to design sensor peptide substrates that are highly selective for your targets of interest.
Each Kinase-Selective Lysate Substrate can be purchased as lyophilized 1mg aliquots. Each mg is sufficient for 1,500 reactions at 15 μM substrate in a 384-well plate (25 μL reaction volume).
Bulk Pricing available.
Cell Lysate Assay Reagent Pack
AQT-LRP
$600
Designed for end user flexibility, incorporate our optimized reagents into your workflow. These reagent packs include sufficient volumes of reaction reagents and cell extraction reagents to perform 2,000 reactions in a 384-well plate (25 μL reaction volume).
Includes:
- ATP, EGTA, DTT, Enzyme Reaction Buffer and Enzyme Dilution Buffer
- PhosphoPreserve Cell Extraction Buffer, Protease Inhibitor and Phosphatase Inhibitor Cocktails
Cell Lysate Assay Controls
Contact Us For Pricing
Ready to scale up from 100 assays but still want the positive controls we used to develop and validate the assay?
Contact us at hello@assayquant.com and we will work with you to get the right amount of controls for your experiment.
We Have Validated Assays For a Small Panel Of Kinase Targets With Many More In Development!
A Direct, Continuous Fluorescence System for Studying Kinase Activity and Cell Signaling In Unfractionated Lysates and Tissue Homogenates
AssayQuant’s PhosphoSens detection technology sets a new standard for kinase research with a growing portfolio of highly selective peptide substrates that enable functional enzymatic activity quantification by monitoring phosphorylation at the substrate level in real time.
Unlike phosphoprotein assays such as Western blotting or ELISA that measure phosphorylation state only as a proxy, PhosphoSens delivers true enzymatic activity at the substrate level. Every well generates a continuous fluorescence signal and a complete progress curve, revealing how fast a kinase is working, how strongly an inhibitor reduces activity, and how pathway dynamics differ under stimulatory or inhibitory conditions.
Designed to meet the needs of modern discovery programs, PhosphoSens Lysate Assays allow you to study kinase activity where biology happens.
Available in flexible formats — from evaluation kits to bulk substrates and supporting reagents — these tools provide reproducible, high-quality data for pathway biology, hit validation, inhibitor profiling, and translational decision-making — helping you move beyond static phosphorylation measurements to direct functional insights.
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.
Unlike phosphoprotein assays that only track phosphorylation state as a proxy, PhosphoSens™ Lysate Assays directly measure functional kinase activity at the substrate level. The result: higher confidence in your findings and a deeper understanding of how compounds behave in native biology.
Explore sample data that uncovers pathway-specific kinase dynamics across diverse cell models — critical insights that we enable
Direct, Real-Time Detection of Kinase Activity in Complex Samples
AssayQuant's Cell Lysate Kinase Assays combine PhosphoSens Detection Technology with high-throughput peptide synthesis to design sensor peptide substrates that are highly selective for your targets of interest.
These Kinase-Selective Lysate Substrates are developed with our readout molecule, Sulfonamido-oxine (Sox), covalently attached via a cysteine residue (native or introduced) in close proximity to the Serine, Threonine, or Tyrosine phosphorylation site (± 2-5 residues).
The Sox fluorophore reports peptide phosphorylation by the target kinase via chelation-enhanced fluorescence (ChEF). The fluorescence-sensing mechanism is based on the chelate effect introduced by phosphorylation of the Ser/Thr/Tyr residue proximal to CSox, which enhances magnesium (Mg²⁺) binding affinity compared to the unphosphorylated species, and results in increased fluorescence emission intensity (2-10-fold).
In this way, CSox-modified peptide substrates provide a fluorescent intensity signal that is directly proportional to the phosphorylation level of the substrate, enabling continuous/real-time kinetic measurements of kinase activity in medium to high throughput (96−1536 well plate).
Prepare your Sample
Grow cells (+/- stimulus), aspirate medium and wash, and add PhosphoPreserve Cell Extraction Buffer with Protease and Phosphatase Inhibitors Cocktails to lyse the cells.
Add
Sample is added to reaction mix containing a Sensor Peptide Substrate, catalyzing phosphotransfer from ATP to the substrate in real time.
Read
Add plate to reader and monitor kinase activity throughout the reaction. Signal is directly proportional to the phosphorylation level of the substrate.
From Selective Substrates to Functional Insights
Our peptide substrates are engineered to be highly selective, ensuring that kinase activity can be measured directly even in the complexity of unfractionated lysates. This design eliminates interference from other kinases and background phosphorylation, allowing the signal to reflect true catalytic activity. By pairing substrate precision with continuous detection, PhosphoSens® assays turn raw phosphorylation events into clear, functional insights into enzyme behavior and inhibitor response.
Selective Kinase Substrate Development
While our current portfolio of biochemical assays are designed for purified kinases and optimized for activity and sensitivity, running assays in complex samples requires an added layer of selectivity. That’s because lysates contain many active kinases, requiring our new sensors to be engineered to detect the intended target without interference—ensuring accurate, meaningful data in complex sample types. To develop these substrates, we offer Custom Assay Development Services which focuses on a Milestone-based approach.
This careful substrate design ensures that PhosphoSens® assays report true catalytic activity, even in the complexity of cell lysates — a key advantage over phosphoprotein approaches.
Screened 123 candidate peptides from derived from native substrate sequences.
Identified AQT0491, with high activity but moderate selectivity.
Screened 259 sequences for ERK1/2 activity and selectivity.
Selected optimized single amino acid substitutions that enhance performance.
Combined substitutions to generate 194 peptide variants.
Top-performing peptide, AQT1076, improved selectivity 10x and ERK2 activity 1.5x over AQT0491.
Measure Function, Not Just Phosphorylation
Phosphoprotein assays only tell you whether a site is phosphorylated. PhosphoSens® assays go further — directly measuring catalytic activity in unfractionated lysates and delivering real-time progress curves. This eliminates uncertainty from antibody variability, off-target phosphorylation, or misleading proxy readouts.
Phosphoprotein Assays (WB/ELISA)
PhosphoSens Lysate Assays
Western blot detects PDGF-induced phosphorylation of AKT at Ser473 — one of more than 50 possible sites on AKT. Because phosphorylation can be activating or inhibitory, and inhibitor compounds can artificially elevate phospho-signals, phosphorylation alone does not reliably indicate true kinase activity.
Using the AQT0982 sensor peptide, PhosphoSens® Lysate Assays revealed a 7.9-fold activation of AKT activity in NIH-3T3 lysates treated with PDGF. Activity was eliminated by heat inactivation or selective AKT inhibitors, confirming assay specificity. Unlike phosphorylation snapshots, these assays deliver dynamic activity profiles in every well.
Study Kinase Enzyme Activity Where Biology Happens
Most kinase assays overlook biological complexity.
To address this challenge in protein kinase inhibitor (PKI) development, we designed a kinase activity assay that delivers mechanistic insight and biological relevance.
Download our poster to learn how we are developing Selective Sensor Peptides that directly quantify kinase activity in crude cell lysates and tissue homogenates.
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Revolutionizing Kinase Research and Drug Development with Continuous Activity Detection in Complex Biological Samples
By using unfractionated cell lysates or tissue homogenates, our assays let you measure kinase activity in a native, biologically relevant environment. This enables you to examine kinase complexes from multiple sample types and link target inhibition to broader signaling network status and disease relevance.
Unlike simplified biochemical assays, our format maintains the complexity of the cellular milieu, capturing key factors that affect kinase behavior and inhibitor performance in vivo:
Cellular Components
Native proteins, lipids, nucleic acids, and cofactors that form functional complexes.
Post Translational Modifications (PTMs)
Natural modifications that regulate kinase activity and interactions.
Signaling Networks
Dynamic feedback and crosstalk, including off-target enzymes that impact selectivity and potency.
Our PhosphoSens™ Lysate Assays don’t just measure enzyme activity—they show how compounds behave in real cellular environments. View sample data that highlights pathway-specific kinase responses across multiple cell models, revealing insights you won’t see with traditional endpoint assays:
Shop Cell Lysate Kinase Assays By Target
Use the table below to find the Cell Lysate Kinase Assay that matches your target of interest. Each Kinase-Selective Lysate Substrate is identified by its unique AQT code (e.g., AQT1076).
To place an order, simply email us with the desired product format:
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AQTxxxx-KL-100: 100-assay Lysate Kit
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AQTxxxx-KL-1000: 1,000-assay Lysate Kit
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AQTxxxx-B-01: 1 mg of selective lysate-compatible substrate
Need a quote or help choosing the right configuration?
Click "Request a Quote" below or reach out directly to our team.
| Target Name | HGNC Approved Full Name | Kinase-Selective Lysate Substrate | Sensor Peptide MW (g/mol) |
Assay Validation Report | Target Specific Protocol |
|---|---|---|---|---|---|
| ERK1/2 | mitogen-activated protein kinase (MAPK3/1) | AQT1076 | 2372.95 | LINK > | LINK > |
| AKT1/2/3 | AKT Serine/Threonine Kinase 1/2/3 | AQT0982 | 3204.69 | LINK > | LINK > |
| GSK3A/B | glycogen synthase kinase 3 alpha/beta | AQT1121 | 2005.92 | LINK > | LINK > |
| DNA-PK | protein kinase, DNA-activated, catalytic subunit | AQT0440 | 1963.1 | LINK > | COMING SOON > |
| JNK | mitogen-activated protein kinase | AQT1196 | 3162.30 | LINK > | COMING SOON > |
Download Our Comprehensive Cell Lysate Kinase Assay Kit Components Tables
Looking for more detail? Download our complete product list, which includes component tables for each lysate assay.
A Continuous Kinetic Assay to Quantitate Specific Protein Kinase Activity in Unfractionated Cell Lysates
This poster will fully describe the methods and results pertaining to ERK-selective sensor peptide development and validation and the ability to extend to other kinases of interest.
Additional Targets In Development - Subscribe for updates!
We are actively developing Cell Lysate Kinase Assays for the following targets: PIM, P38, CDKs and more!
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