Frequently Asked Questions

Check out our frequently asked questions below.
If you still have questions, please contact us.

Protein Kinases

Pack size of protein kinase products?

Starting from as small as 5ug up to bulk volume, you can purchase Carnas kinase products for your requested amount.Some kinases are available only for the 5ug size. 50ug is a minimum size for inactive & inactive-mutant kinases.

I am interested in protein kinase which is not on the list.

Please inquire us. Some may be under development. Also, Carna can produce mutated forms of specific protein kinase upon request.

What is the origin of the kinase product?

All protein kinases among the list are human recombinant protein.

How are the protein kinases manufactured?

The majority of Carnas kinases are manufactured using a baculovirus expression system, and a few use an E.coli. expression system. For an overview of Carnas methods, please follow the kinase products page and click on the product name of interest to view the complete “Product description.”

Are the kinases sold in an activated form?

Yes. If a kinase demonstrates low activity post-expression or a lag phase after initiation of the kinase reaction, Carna activates it by ATP treatment, co-expression or incubation with its upstream kinase(s), GST-tag removal by protease, or another activation method, depending on the nature of the kinase. Please refer to Carnas technical note, “Carna Coffee Break No.1” for details.

Can I purchase inactive kinase products?

Yes. Carna offers inactive kinases and inactive mutant kinases related to the MAP kinase cascade. These can be used as substrates and in other applications. Please see the product list on our kinase products page.

Is it possible to cleave the affinity tag from the kinases?

Yes. All of Carnas kinases contain a cleavage site between the kinase sequence and the tag. The GST-tag can be cleaved using Precission protease (Cytiva), and the his-tag can be cleaved using TEV protease. Carnas biotinylated kinases contain the DYKDDDDK tag between the kinase and the biotinylated site, where the biotinylated site can be cleaved using enterokinase.

How many biotins do the biotinylated kinases contain?

All of the biotinylated kinases we sell contain a single biotin per molecule.

How dos Carna assure the quality of the kinases?

Carna determines the purity of the kinases using SDS-PAGE gels; the activity is determined in a kinase assay by examining phosphorylation of its substrate.

I’m concerned kinase activity may vary batch-to-batch.

Since Carna use a highly reproducible manufacturing method, and Carna monitors the activity of each batch, activity differences between batches is minor for most of the kinase products. If you would like to confirm any possible activity or purity difference between batches, please contact us.

How dos Carna confirm the identity of the kinase products?

Carna performs mass spectrometry for peptide fingerprinting to confirm the correct sequence.

How can I obtain the sequence(s) of the kinase(s)?

By clicking on the specific kinase name on our product information page, you can view sequence information under the “AMINO ACID SEQUENCE”, shown at the top of the page.

Which types of kinase products are best suited for use in binding assays?

We recommend Carnas biotinylated kinases for binding studies because of their high purity and small molecular weight label.

Do kinase products have associated Safety Data Sheets?

Carnas kinases do not require Safety Data Sheets.

Where are the kinases manufactured?

All kinases are manufactured at Carna Biosciences’ in-house laboratory. 

How are the kinases shipped?

All of the kinases are shipped on dry ice after 1-2 weeks upon order. 

As soon as you receive the shipment, please transfer the kinase(s) to a -80℃ freezer (or colder). Proper storage is essential to shelf life. Once you thaw the kinase, aliquot the remainder to avoid freeze-thaw cycles.

What buffer would be best to dilute Carna's kinase proteins?

Please use the composition of the stock buffer described on a Product Information sheet that is attached to each product.

Mobility Shift Assay(MSA)/IMAP™ & ADP-Glo™ Kinase Profiling Services

Where is the Assay performed?

The Assay Service is provided and performed by Carna Biosciences while Kinase Logistics acts as a distributor.

Why are assays performed at an ATP concentration equal to the Km value?

For ATP-competitive inhibitors, the dependencies between the half maximal inhibitory concentration (IC50) and ATP concentrations are described by the Cheng-Prusoff equation (IC50 = Ki + Ki/Km×[ATP]). By representing the ATP concentration with its Km value, the IC50 reflects 2×the Ki value. Thus, IC50 values become a direct and comparable measure of affinity between the inhibitor and the investigated kinases.

How do I set the compound test concentration?

We recommend that you first measure % inhibition at 1-10μM, and then choose compounds with strong inhibitory activity. For follow up IC50 determinations, you can reference the results of their % inhibition to set appropriate test concentrations.

How do I check on the details of profiling service?

Please find the information inside the latest kinase profiling book. Detailed conditions can be found inside the book.

How do I prepare test samples?

The required volume of samples is 500uL each if less than 100 target kinases, 1000uL each for over 100 kinases. Please prepare samples in 100% DMSO, 100x of the highest test concentration you selected. Please click here for more details.

Is it possible for Carna to store the compounds that have been tested for use in follow up tests?

Yes. As a rule, we typically discard compounds 3 months after the date of submitting the result report, so we will store your compound during that time period. If you wish to extend the time we keep the compounds, please contact us.

What assay format(s) does Carna employ and why for each target?

We typically utilize Mobility Shift Assay (MSA) as a first choice because it is easy to operate, highly reproducible, and can detect both phosphorylated and non-phosphorylated substrates simultaneously. However, a substrate for MSA should be a peptide which has only one phosphorylation site in the sequence and with a pI near neutrality. When such substrate is not available, we deploy a different detection method. With exceptions, ADP-Glo™ is a chosen platform for kinases whose substrates are lipids and IMAP is chosen if its peptide substrate has more than two phosphorylation sites. Most targets are performed using the MSA format.

What is the utility of profiling at 1mM ATP?

The 1mM ATP profiling assays are useful in predicting the potential intracellular selectivity of your inhibitor using conditions approaching physiological ATP concentrations. Profiling at 1mM ATP can also assist to identify possible non ATP-competitive inhibitors when compared with IC50 data generated at ATP Km.

How do I appy for the profiling service?

Please select a assay platform from Profiling Service top page, and refer to "Guide for our service customer" for service details. Or, please feel free to contact us and we're happy to guide you through!

When will I receive my profiling result?

Normally, 2-3 weeks after the receipt of compounds, you will receive a result in an encrypted file via email.

What does the "preincubation" profiling include?

The service incorporates a 30 minute pre-incubation at room temperature with the test compounds and the investigated kinase prior to measuring the activity in our standard method of MSA. This is useful to assess potencies of compounds with slow binding kinetics.

Is the panel assay available?

Carna is offering four unique pre-selected panels. You can also select additonal kinases to the combination of a panel.

What does “Km bin” mean, with reference to the ATP concentration?

For assays run at ATP Km value, we create a series of groups, or ‘bins’ of ATP concentrations near the Km, but round numbers. For example, if a kinase has an ATP Km value of 47 μM, it will be grouped with other kinases with similar ATP Km values and performed at 50 μM ATP. This ensures that each kinase assay is performed at an ATP concentration very close to the Km value, and at the same time allows for efficiency of running a large number of kinase assays simultaneously.

What reference compounds are used for Carna’s profiling assays?

We use staurosporine for most Mobility Shift Assay(MSA)/IMAP™ and ADP-Glo™ kinase assays, or if availble, we employ some specific inhibitor to a given kinase. Please click on each target kinase on respective service page, and you'll find what reference is employed in each assay.
Mobility Shift Assay(MSA)/IMAP™
ADP-Glo™ kinase assays

Is it possible to see an example of the report and data?

Yes, sample reports are available to show you. Please contact us.

NanoBRET™ TE Intracellular Kinase Cell-Based Assay Services

Where is the Assay performed?

The Assay Service is provided and performed by Carna Biosciences while Kinase Logistics acts as a distributor.

Can I designate which tracer is used in the assay?

We prioritize to choose the tracer specified by Promega for each kinase and employ it for our service after our internal validation. If you would like us to use another tracer, please consult us.

How can I find out which tracer is used in my assay?

As a general rule, we use the tracer recommended by Promega. We occasionally choose a different tracer if our in-house assay results indicate this is preferable. The tracer used will be indicated in the study report. If you have any tracer questions or are interested in a kinase assay not listed on the Promega website, please contact us.

What is the concentration of the tracer used in Residence Time determinations?

As a general rule, the tracer concentration is set at 2µmol/L in cases where the tracer concentration used in the IC50 determination exceeds 1µmol/L. Otherwise, it is set at 1µmol/L.

Is it possible to disclose the name of reference compound in advance?

Yes, please inquire.

Do you accept assay requests for kinases not listed in the current portfolio?

Yes, it may be possible. Please contact us.

Where can I find information regarding the position of NanoLuc® in the fusion kinases?

NanoLuc® may be fused to either the N-terminus or C-terminus of the kinase. Referring to the column titled Vector Name, accessed on Promega website, kinases fused to NanoLuc® on N-terminus are indicated as “NanoLuc®-kinase name”, kinases fused to NanoLuc® at the C-terminus are indicated as “kinase name-NanoLuc®”. The name of the vector will be indicated in the study report. Please contact us if you are interested in any kinase(s) not listed on the Promega website.

Why is a compound concentration of IC80-90 recommended for Residence Time determinations?

Ideally, the dissociation of bound compound from the kinase should be evaluated when compound occupies 100% of the kinase with no residual unbound compound. However, if the compound concentration is set beyond IC80-90, it might become difficult to remove the residual unbound compound completely by wash, which could affect accurate measurement. Therefore, it is recommended to perform the testing at the IC80-90 concentration.

Is it possible to see an example of the report and data?

Yes, sample reports are available. Please inquire.

What is the concentration of tracer used for IC50 determinations?

In general, we follow the application notes shown on Promega’s website above. Typically, the concentration is around the EC50 of the tracer dose response curve. The upper limit is 2 µmol/L.

How is the BRET ratio calculated?

The BRET ratio is calculated following the equation below using the donor signal (NanoLuc® fused kinase) and the acceptor signal (tracer).

BRET ratio (mBRET)

= {(Acceptor_sample/Donor_sample) – (Acceptor_no tracer/Donor_no tracer)} ×1000

Acceptor_sample: The acceptor signal of the sample or DMSO control in the presence of tracer.
Donor_sample: The donor signal of the sample or DMSO control in the presence of tracer.
Acceptor_no tracer: The acceptor signal of DMSO control in the absence of tracer.
Donor_no tracer: The donor signal of the DMSO control in the absence of tracer.

Assay Kits & Development

Can I order IMAPTM beads?

IMAPTM beads can be sold upon request.

How do I refer to the protocol of assay kit in advance of ordering?

Please select an assay kit platform from an Assay Kit top page first, and you'll find a downloadable sample protocol on each kit page.

Can I order the component separately?

Only components of Mobility Shift Assay kits are availabe after your first purchase of the kit. For our discontinued TK-ELISA Assay Kits, all kit components remain available for your purchase.

When will I receive the product?

Our assay kit is custom-made. Normally, 2-3 weeks for the delivery.

Is there anything I have to prepare before using assay kits?

For use of IMAPTM, ELISA, and TR-FRET kits, some materials need to be prepared by you. Please select an assay kit platform from an Assay Kit top page first, and check what additional materials are required in each sample protocol on respective assay kit page.

What type of plate I have to prepare?

Please refer to each protocol for the name of manufacturer and catalogue number of plate which Carna recommends.

What components are included in each kit?

Please select an assay kit platform from an Assay Kit top page first, and you'll find what components are included in each kit.

What is the minimum order size of assay kits?

100dp per set for ELISA and 400dp for other platforms.

Detection of Protein: Protein Interactions

Are Carna’s luciferase assays applicable to the detection of PPIs?

Yes. These assays have been used to detect signals not only for GPCR studies but also for protein protein interactions inside a cell, such as FKBP-FRB binding. Whether the split luciferase generates a detectable signal when measuring protein protein interactions relies on various factors---protein structural stability, expression level inside a cell, proximity of the two luciferase fragments during the interaction, etc. If you wish to develop a PPI assay by the use of Carnas luciferase technology, please contact us.

What should I use as the luciferase substrate?

We recommend using Carna’s Split Glow Cell Assay Reagent (PXR-SG001), developed exclusively for our Split Luciferase Assay. Its composition is optimized for this assay to generate the brightest luminescence signal. When detecting a signal inside a living cell (as opposed to a cell lysate), use D-Luciferin (approximately 1.0 mM) dissolved in PBS or HBSS reagent.

What instrument should I use for reading?

Use any plate reader applicable to bioluminescence detection, or a tube-type luminometer. A detector with higher sensitivity is better.

What are the advantages of Carna's luciferase technology compared to other similar systems?

Emerald luciferase in our split luciferase assay shows higher stability inside a cell and can emit a signal fifteen times brighter than firefly luciferase. Using our Split Glow Cell Assay Reagent (PXR-SG001), which can reduce background emission, you can detect stimuli-responsive PPI signals with high sensitivity. Its ability to detect a signal in cells for GPCR screening in just ten minutes after ligand stimulation also indicates that Carna’s luciferase is highly useful for high throughput screening of compounds. Its applicability for imaging in living cells and animals additionally makes it a valuable tool in evaluating compounds in a living cell or animal.

Are Carna’s luciferase assays applicable for imaging?

Yes. The emerald luciferase used in our split luciferase system emits a very strong signal, which enables you to image real time signals at a single cell level for several hours. Please see the video of GPCR-arrestin imaging data on our website. Use diluted D-Luciferin in medium (approximately 1.0 mM) for the substrate in a living cell. Please contact us for detailed assay conditions.

Contact us