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Our scientists can help you choose the right assay format, substrate, and enzyme for your experiment.
About ULK1
ULK1 (unc-51 like autophagy activating kinase 1) belongs to the ULK serine/threonine kinase family, which also includes ULK2, and serves as the primary mammalian ortholog of yeast Atg1. ULK1 functions as the apical kinase of the autophagy initiation complex, forming a heterotetrameric complex with ATG13, FIP200, and ATG101. Its activity is tightly regulated by two master metabolic sensors: mTORC1 phosphorylates ULK1 at Ser757 to suppress it under nutrient-rich conditions, while AMPK phosphorylates ULK1 at Ser317 and Ser777 to activate it during energy stress. Key substrates include Beclin-1, ATG14, and FUNDC1. ULK1 sits at the crossroads of nutrient sensing, mitophagy, and selective autophagy pathways, making it critically relevant to cancer (where autophagy supports tumor cell survival), neurodegeneration, metabolic disease, and infectious disease. Its unique position as a druggable kinase upstream of the entire autophagy cascade renders ULK1 a compelling oncology and neurodegeneration drug target.
Why PhosphoSens for ULK1?
ULK1 presents several assay challenges: it has a relatively low catalytic rate, requires careful ATP concentration management because physiological ATP levels differ markedly from Km values, and is susceptible to compound interference in endpoint luminescence formats like ADP-Glo. HTRF and radiometric assays introduce additional complexity through antibody cross-reactivity and radioactive waste handling. PhosphoSens continuous kinase assays overcome these hurdles by generating real-time fluorescent progress curves at physiological ATP concentrations, enabling direct capture of kinact/KI for covalent inhibitor characterization and accurate IC50 determination without endpoint artifacts. The continuous format also detects time-dependent inhibition and compound instability that static endpoint formats miss, making it especially powerful for profiling ULK1 inhibitors across diverse chemotypes in drug discovery campaigns.
Key Pathways:
Autophagy initiation
mTORC1 signaling
AMPK energy sensing
Mitophagy
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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 ULK1 Activity Assays
Continuous, real-time fluorescent assays optimized for quantitative ULK1 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 - AQT0332
Ready-to-use assay kits containing substrate and all essential reagents.
Kit Contents
- Optimized PhosphoSens® substrate (AQT0332)
- 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 AQT0332
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
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Request a QuoteNo PhosphoSens-Red format is currently available for ULK1.
Ready to request pricing for ULK1?
Select a kit, substrate, or enzyme above. Our team will confirm pricing, availability, and any applicable bundle discounts.
Request a QuoteActive Recombinant Enzymes for ULK1
Wild-type and mutant forms of ULK1 for assay development, kinase profiling, and mechanistic studies. Enzymes are supplied active and optimized for PhosphoSens® substrates.
ULK1, Active
Human • Baculovirus-Insect Cells
Technical Specifications
- Catalog: AQT-U01-11G
- Species: Human
- Expression System: Baculovirus-Insect Cells
- Storage Buffer: Supplied as sterile 50 mM Tris-HCl, pH 7.5, 50-300mM NaCl, 10mM glutathione, 0.1mM EDTA, 0.25-1.0mM DTT, 0-0.1mM PMSF, 10-25% glycerol
- Molecular Weight: ~125 kDa
- Purity/Activity: For specific information on a given lot, see related technical data sheet.
- Storage Conditions: Store product at -70°C. For optimal storage, aliquot target into smaller quantities after centrifugation and store at recommended temperature. For most favorable performance, avoid repeated handling and multiple freeze/thaw cycles.
Available Sizes:
Price: $$378.00
Request a QuoteFrequently Asked Questions: ULK1 Assays
What substrate does AssayQuant use for ULK1 kinase assays?
AssayQuant offers PhosphoSens peptide substrates derived from validated ULK1 phosphorylation sites, including sequences from ATG13 and Beclin-1, conjugated to the Sox fluorophore. Phosphorylation is detected continuously in real time without antibodies or secondary reagents, providing clean kinetic data even at low enzyme concentrations typical of ULK1 assays.
Can the PhosphoSens ULK1 assay be used at physiological ATP concentrations?
Yes. Unlike ADP-Glo or coupled enzyme assays that require ATP titration optimization or compromise at sub-Km concentrations, PhosphoSens assays function across a wide ATP range including 1 mM physiological ATP. This is critical for ULK1 inhibitor profiling because compound potency rankings can shift substantially between low and physiological ATP, directly impacting translational relevance of IC50 values.
How does the PhosphoSens assay handle time-dependent or covalent ULK1 inhibitors?
Because PhosphoSens measures fluorescence continuously, full progress curves reveal onset-of-inhibition kinetics in a single experiment, enabling direct fitting of kinact and KI parameters for covalent or slow-binding inhibitors. Endpoint assays collapse this rich temporal information into a single data point, often masking time-dependent behavior and leading to misclassification of inhibitor mechanism.
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™ ULK1 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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