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Our scientists can help you choose the right assay format, substrate, and enzyme for your experiment.
About BLK
BLK (B lymphoid tyrosine kinase) is a non-receptor tyrosine kinase belonging to the Src family, which shares a conserved domain architecture comprising SH2, SH3, and catalytic SH1 domains. BLK is predominantly expressed in B lymphocytes and plays a critical role in B-cell receptor (BCR) signaling, proliferation, and differentiation. Upon BCR engagement, BLK is activated through Lyn-mediated transphosphorylation at its activation loop tyrosine (Y389) and dephosphorylation of its inhibitory C-terminal tyrosine by CD45 phosphatase. Key substrates include CD79a/b (Igα/Igβ), BLNK, and downstream effectors of the PI3K and MAPK cascades. BLK has emerging roles in pancreatic beta-cell function and insulin secretion regulation. Dysregulation of BLK is implicated in systemic lupus erythematosus (SLE), rheumatoid arthritis, type 1 diabetes, and B-cell malignancies including diffuse large B-cell lymphoma. Its restricted tissue expression makes BLK an attractive therapeutic target for autoimmune diseases and B-cell-driven cancers with a potentially favorable selectivity window.
Why PhosphoSens for BLK?
Characterizing BLK inhibitors presents significant challenges: BLK shares high active-site homology with Src-family members LCK, LYN, and FYN, demanding sensitive selectivity profiling. Conventional endpoint assays such as ADP-Glo and HTRF require fixed ATP concentrations that obscure true kinetic constants, miss time-dependent inhibition, and cannot detect covalent or slow-binding mechanisms. Radiometric filters introduce quench artifacts and radioactive waste. AssayQuant's PhosphoSens CSox-based peptide substrates enable continuous, real-time fluorescence monitoring of BLK-mediated phosphorylation using physiological ATP concentrations, generating full progress curves that accurately capture Km(ATP), IC50, Ki, and covalent kinact/KI parameters. This approach eliminates endpoint variability, reduces assay steps, and enables rapid selectivity counter-screening across the Src family in a single-day workflow.
Key Pathways:
B-cell receptor (BCR) signaling
PI3K/AKT/mTOR signaling
MAPK/ERK signaling
JAK-STAT signaling
Talk to a Scientist
Have questions about BLK assay design, selectivity panels, or covalent inhibitor characterization?
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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 BLK Activity Assays
Continuous, real-time fluorescent assays optimized for quantitative BLK 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 - AQT0794
Ready-to-use assay kits containing substrate and all essential reagents.
Kit Contents
- Optimized PhosphoSens® substrate (AQT0794)
- 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 AQT0794
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 BLK?
Select a kit, substrate, or enzyme above. Our team will confirm pricing, availability, and any applicable bundle discounts.
Request a QuoteTRF BLK Screening Assays
Robust endpoint TRF assays optimized for high-throughput screening and quantitative BLK 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 - AQT0515
Ready-to-use TRF assay kits containing substrate and essential reagents.
Kit Contents
- Optimized PhosphoSens® substrate (AQT0515)
- 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 AQT0515
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 BLK?
Select a kit, substrate, or enzyme above. Our team will confirm pricing, availability, and any applicable bundle discounts.
Request a QuoteActive Recombinant Enzymes for BLK
Wild-type and mutant forms of BLK for assay development, kinase profiling, and mechanistic studies. Enzymes are supplied active and optimized for PhosphoSens® substrates.
BLK, Active Full Length
Human • Baculovirus-Insect Cells
Technical Specifications
- Catalog: AQT-B02-10G
- Mutation: Full Length
- 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: ~84 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: $$348.00
Request a QuoteFrequently Asked Questions: BLK Assays
What peptide substrate does AssayQuant recommend for BLK kinase assays?
AssayQuant offers PhosphoSens CSox-based peptide substrates optimized for Src-family tyrosine kinases, including substrates derived from CD79a ITAM sequences that are efficiently phosphorylated by BLK. These substrates incorporate a chelation-enhanced fluorophore that ratiometrically reports phosphorylation in real time, enabling continuous kinetic measurements without antibodies or secondary detection reagents.
Can PhosphoSens assays distinguish BLK activity from other Src-family kinases in selectivity panels?
Yes. Because PhosphoSens assays run continuously under identical physiological ATP conditions, you can directly compare kinetic parameters (kcat/Km, IC50, Ki) for BLK versus LCK, LYN, FYN, and SRC in parallel wells on the same plate. This eliminates normalization artifacts that arise when comparing endpoint assays run at different ATP concentrations, making selectivity profiling across the Src family quantitatively reliable.
How does the PhosphoSens platform handle covalent or slow-binding BLK inhibitors?
Full real-time progress curves generated by PhosphoSens directly reveal time-dependent inhibition signaturesu2014such as curved progress lines or progressive enzyme inactivationu2014that are completely invisible to endpoint ADP-Glo or HTRF readouts. kinact and KI values for covalent inhibitors can be extracted directly from progress curve analysis using established kinetic models, enabling accurate characterization of irreversible or slowly reversible BLK inhibitor candidates.
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™ BLK 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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