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PhosphoSens CDK2/CycE1 Protein Kinase Assays, Substrates & Recombinant Enzymes
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About CDK2/CycE1
Cyclin-dependent kinase 2 (CDK2) is a serine/threonine kinase and founding member of the CDK family, which collectively orchestrate cell cycle progression, transcription, and DNA damage responses. CDK2 activity requires association with its regulatory partner Cyclin E1 (CCNE1), forming the CDK2/CycE1 complex that drives the G1-to-S phase transition. Upon activation, CDK2/CycE1 phosphorylates the retinoblastoma protein (Rb) at multiple sites, releasing E2F transcription factors to promote S-phase gene expression. Additional substrates include p27Kip1, CDC6, NPAT, and components of the pre-replication complex. CDK2 is negatively regulated by CIP/KIP family inhibitors (p21, p27) and by inhibitory phosphorylation at Thr14/Tyr15 via Wee1. Dysregulation of CDK2/CycE1 signaling is implicated in breast, ovarian, colorectal, and gastric cancers, frequently through CCNE1 amplification or loss of p27. Its central role in driving aberrant S-phase entry makes CDK2 a compelling oncology drug target, with selective inhibition sought to avoid CDK1-related toxicity.
Why PhosphoSens for CDK2/CycE1?
Developing selective CDK2 inhibitors demands high-sensitivity assays capable of resolving potency differences among structurally similar CDK family members and characterizing slow-binding or covalent inhibitor mechanisms. Traditional endpoint methods such as ADP-Glo and HTRF require quenching or antibody-based detection, masking transient kinetic events and introducing well-to-well variability that obscures true IC50 shifts. Radiometric assays add safety and throughput burdens. PhosphoSens continuous fluorescent assays monitor CDK2/CycE1-mediated substrate phosphorylation in real time at physiological ATP concentrations, yielding full progress curves that capture Ki, kon, and koff directly. This enables accurate kinact/KI determination for covalent candidates and true competitive versus slow-tight-binding discrimination — critical for prioritizing next-generation selective CDK2 inhibitors and profiling selectivity against CDK1 and CDK4/6.
Key Pathways:
Cell Cycle G1/S Transition
Rb/E2F Signaling
DNA Damage Response
PI3K/AKT/mTOR Crosstalk
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How pricing works:
Select a kit or substrate below, then request a quote. Bundle discounts apply automatically.
Select a kit or substrate below, then request a quote. Bundle discounts apply automatically.
Real-Time CDK2/CycE1 Activity Assays
Continuous, real-time fluorescent assays optimized for quantitative CDK2/CycE1 activity measurements, IC50 determination, and mechanistic studies.
Assay Format: Continuous kinetic fluorescence (real-time)
PhosphoSens-Kinetic assays directly quantify enzyme activity by continuously monitoring substrate phosphorylation or dephosphorylation in real time, generating a full progress curve in every well.
Learn more about PhosphoSens-Kinetic →Need pricing or availability? Select a kit or substrate to request a quote below.
Kits
PhosphoSens-Kinetic Kinase Activity Kit - AQT0297
Ready-to-use assay kits containing substrate and all essential reagents.
Kit Contents
- Optimized PhosphoSens® substrate (AQT0297)
- ATP, DTT, EGTA, Reaction Buffer & Dilution Buffer
Automatically save 10% when bundling 10ug recombinant enzyme with your 1,000 assay kit. View enzymes
Price: $425
Substrate
PhosphoSens Kinase Substrate AQT0297
Bulk PhosphoSens® substrate for assay development and high-throughput workflows.
Specifications
Automatically save 10% when bundling Reagent Packs with your substrate. View Reagent Packs
Price: $2795
Ready to request pricing for CDK2/CycE1?
Select a kit, substrate, or enzyme above. Our team will confirm pricing, availability, and any applicable bundle discounts.
Request a QuoteTRF CDK2/CycE1 Screening Assays
Robust endpoint TRF assays optimized for high-throughput screening and quantitative CDK2/CycE1 activity measurement in plate-based workflows.
Assay Format: Time-resolved fluorescence (TRF, endpoint)
PhosphoSens-Red assays use europium-based time-resolved fluorescence detection to enable robust, plate-based quantification of enzyme activity, making them well suited for high-throughput screening workflows.
Learn more about PhosphoSens-Red →Need pricing or availability? Select a kit or substrate to request a quote below.
Kits
PhosphoSens-Red Kinase Activity Kit - AQT0255
Ready-to-use TRF assay kits containing substrate and essential reagents.
Kit Contents
- Optimized PhosphoSens® substrate (AQT0255)
- ATP, DTT, EGTA, Reaction Buffer & Dilution Buffer
- Europium Detection Solution
Automatically save 10% when bundling 10ug recombinant enzyme with your 1,000 assay kit. View enzymes
Price: $455
Substrate
PhosphoSens Kinase Substrate AQT0255
Bulk substrate for PhosphoSens-Red TRF assays and high-throughput workflows.
Specifications
Automatically save 10% when bundling Reagent Packs with your substrate. View Reagent Packs
Price: $2795
Ready to request pricing for CDK2/CycE1?
Select a kit, substrate, or enzyme above. Our team will confirm pricing, availability, and any applicable bundle discounts.
Request a QuoteNo recombinant enzymes are currently available for CDK2/CycE1.
Frequently Asked Questions: CDK2/CycE1 Assays
What substrate does AssayQuant use for CDK2/CycE1 activity assays?
AssayQuant offers PhosphoSens CSox-based peptide substrates engineered to be recognized by CDK2/CycE1 with high efficiency. The chelation-enhanced fluorophore reports phosphorylation continuously in real time, eliminating the need for secondary detection reagents and enabling kinetic parameter determination in a single experiment.
Can PhosphoSens assays measure covalent or irreversible CDK2 inhibitors?
Yes. Because PhosphoSens generates full reaction progress curves from the moment of mixing, it directly captures the time-dependent loss of enzyme activity characteristic of covalent inhibitors. This allows accurate kinact/KI determination for CDK2-targeted covalent candidates, data that endpoint assays fundamentally cannot provide.
How does running CDK2 assays at physiological ATP improve data quality?
Many CDK2 inhibitors are ATP-competitive, so artificially low ATP concentrations commonly used in endpoint assays overestimate potency and distort selectivity profiles. PhosphoSens assays operate at near-physiological ATP (1 mM range), producing IC50 and Ki values that better predict cellular activity and support more reliable structure-activity relationship decisions.
Data & Resources
Explore data and documents to support your kinase and phosphatase experiments. Download sample data, protocols and other resources to see how our assays perform and to help you get started in your own lab. All validation data generated using PhosphoSens® assays under recommended conditions.
Sample Report: AQT0734 - EGFR Assay Validation Report
Each validation report provides experimental conditions and data showing:
- Enzyme titration and linearity
- Sensor peptide substrate titration and Km determination
- ATP titration and Km determination
- DMSO titration and assay tolerance
- Inhibitor titration and IC50 determination
Protocol
Inhibitor IC50 Protocol
See how the PhosphoSens-Kinetic Assay can be used to find the IC50 of a kinase inhibitor.
Download Protocol →Webinar
Webinar: Continuous Assay Validation
Discover how continuous assay formats power deep understanding of kinase function. See how PhosphoSens® assays guide inhibitor profiling, selectivity assessment, and mechanistic characterization.
Watch the Webinar →Service
KinSight™ CDK2/CycE1 Profiling
Need broader selectivity data? KinSight profiling runs your compounds across our full kinase panel under identical PhosphoSens conditions.
Learn about KinSight →Stay Informed
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