A Homogenous, Universal Enzymatic Methyltransferase Assay for HMTs

AptaFluor SAH Methyltransferase Assay

AptaFluor SAH Methyltransferase Assay directly measures SAH produced by methyltransferase enzymes during methylation. These enzymes methylate a variety of substrates using S-adenosylmethionine (SAM) as the methyl donor, leaving the common product S-adenosylhomocysteine (SAH). These SAH measurements allow researchers to effectively determine the activity of the methyltransferase enzyme. The assay provides a powerful tool to screen compound libraries for methyltransferase modulators to help find new therapies for disease. 

The kit comes complete with detection reagents required to measure activity. Methyltransferase enzyme is not included in the inhibitor screening assay kit. Please contact us for questions related to acquiring the enzyme.

How does the AptaFluor Methyltransferase Assay Work?

The AptaFluor SAH Methyltransferase Activity Assay determines methyltransferase enzyme activity by directly measuring SAH (S-adenosylhomocysteine) produced during the methylation of a variety of substrates. By directly detecting SAH in a homogenous format, it is possible to perform screening and enzymatic studies with virtually any methyltransferase. 

AptaFluor Methyltransferase technology uses a natural occurring aptamer, or riboswitch, that selectively binds with SAH. The exquisite affinity and selectivity of the riboswitch enables screening and profiling of methyltransferases with unparalleled sensitivity.

The AptaFluor Assay is available with TR-FRET readout. It is a simple mix-and-read format. Perform your enzyme reaction, add the detection reagents, and measure. The simplicity of the system yields robust results that also makes it extremely amiable to HTS.

Direct Detection of SAH with a TR-FRET Readout

Methyltransferase Assay Kit Schematic

For customers who prefer TR-FRET detection. Uses the same filter set as HTRF®.


The most sensitive HTS methyltransferase assay available with an LLD of 0.6 nM SAH. This dramatically reduces enzyme usage and allows the assay to be run at or below Km for SAM.

Easy-to-Use, Mix-and-Read, HTS-Ready

Run your enzyme reaction, add quenching reagent, add AptaFluor reagents, and read your plates. The AptaFluor Assay is compatible with 96, 384, and 1536-well formats. 

AptaFluor Methyltransferase Assay Protocol Outline

Compatible with a Variety of MTase Acceptor Substrates

Toleration of MT acceptor substrates. 100 nM SAH-SAM standard curves were set up in the presence of nucleosomes (10 ng/μL), histone H3-3 (3 ng/μL), Histone H3 (1-21) peptide (10 μM) and Poly d (I-C) (2.5 mU/μL); control wells lacked a MT substrate.

Robust Assay Yields Quality Data

Excellent Z’ under a variety of assay conditions.

PRMT4 enzyme with 0.2 uM or 2 uM SAM and histone substrate as positive controls. PRMT4 and histone substrate as negative control.

Use with Physiological SAM Concentrations Lower than 100nM

SET7/9 Enzyme Titration with Linear Response Curve

Stable Detection of Methyltransferase Activity

Outstanding reagent and signal stability reduces assay variability and allows for automated workflows.

Universal – Use with Virtually Any Methyltransferase

Methyltransferase Enzyem and Substrate Chart

Methyltransferase Assay Services

Interested in moving your program forward, but don't want to bring an assay in-house? Our scientists can help! BellBrook scientists will use their extensive biochemistry and enzymology expertise to work with you and accelerate your methyltransferase program.

Assay Development Services

Lead Discovery Services Include:

  • Inhibitor Screening – To identify or confirm activity with the target.
  • Inhibitor Potency Profiling – Dose-response with target and/or related proteins. Fast IC50 results.
  • Residence Time Measurements – Determination of koff using ‘jump dilution’ enzymatic assay method.
  • Mechanism of Action Studies – Kinetic analysis to define the mode of inhibition.

Contact Us to Learn More

Please fill out the form below. We will respond quickly to get the conservation moving and learn how we can help. We keep things discrete, confidential, and professional.

Far Red TR-FRET Readouts Validated on Major Multimode Readers

SupplierInstrumentTR-FRET Assays
TriStar2S LB 942Click Me ArrowValidated
Mithras2 LB 943Click Me ArrowValidated
CytationTM 5Validated
CytationTM 3Validated
CytationTM 1Validated
SynergyTM H1Validated
SynergyTM 2/H4/4Click Me ArrowValidated
SynergyTM HTXNot Capable
SynergyTM Neo 2Validated
POLARstar® OmegaClick Me ArrowValidated
FLUOstar® OmegaClick Me ArrowValidated
PHERAstar® FSXClick Me ArrowValidated
PHERAstar® Plus/FSClick Me ArrowValidated
CLARIOstar® /PlusClick Me ArrowValidated
VANTAstarTMClick Me ArrowValidated
SenseIn Review
Analyst® GT/HTClick Me ArrowValidated
Gemini® XPS/EMNot Capable
SpectraMax® M2/M2eNot Capable
SpectraMax® M5/M5e/FlexStation® 3Click Me ArrowValidated
SpectraMax® ParadigmClick Me ArrowContact Us
SpectraMax® iD3/iD5Click Me ArrowValidated
EnVision®/EnVision® XciteClick Me ArrowValidated
Infinite® M1000/M1000Pro/Safire2TMClick Me ArrowValidated
Infinite® M200Not Capable
Infinite® F500Click Me ArrowValidated
Infinite® F200/UltraevolutionClick Me ArrowContact Us
SparkTM 10MClick Me ArrowValidated

What's Included

What You Will Need

AptaFluor SAH Methyltransferase Assay Kits

* For custom or bulk orders (over 10,000 wells) please contact us (info@bellbrooklabs.com) for a quote.

Methyltransferases As Drug Targets

Methyltransferases are a diverse family of enzymes that catalyze the transfer of a methyl group from S-adenosylmethionine (SAM or AdoMet), generating S-adenosylhomocysteine (SAH) as a byproduct. Methyltransferases have been associated with a variety of diseases, including cancers, inflammatory diseases, metabolic diseases, and neurodegenerative diseases (Copeland et al., 2009).

Epigenetic regulation has been shown to be a contributing factor in a variety of diseases. The discovery of methyltransferase inhibitors is currently an area of intense activity. Continuing to build an understanding of methyltransferase enzymes is step one. Finding therapeutic methods to reign in overactivity requires selective technologies that can help assess the ability to interact with the target. Robust, HTS-ready assays that are accurate yet flexible provide a powerful tool to accelerate discovery.