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To help shed some light on our services, here are answers to the frequently asked questions about products and orders. You can also leave messages to us if you have more questions, we will contact you in 1 business day.

  • Technical FAQ

  • Ordering FAQ

Q1. Recommendations for reconstitution, storge, etc.

1) We highly recommend storing the protein products as lyophilized powder and reconstituting the protein freshly. For the most of products, the lyophilized powder is more stable than liquid.

2) Please reconstitute the protein following the COA. Avoid repeated freeze-thaw cycles. The reconstituted protein must NOT be aliquoted to less than the minimum aliquoted amount on COA. If it is less than the minimum aliquoted amount on COA, we recommend users to add BSA or HSA for protection. Obviously, the user needs to make sure BSA or HSA doesn’t interfere with the assay they intend to run with the protein. This is critical to protect the protein against surface adsorption loss and inactivation.

3) It is recommended to store at the reconstituted concentration. If the used concentration is lower than the recommended reconstituted concentration, the customer can dilute the reconstituted protein before use; If the used concentration is higher than the recommended reconstituted concentration, the customer should be reconstituted it following the COA first, and then concentrate it to the required concentration.

Q2. Is it possible to store the reconstituted product at 4 degree or at RT?

We strongly suggest NOT to store the reconstituted product at 4 degree or at RT. If you need to use the protein multiple times during a period of time, the best way is to make single use aliquots, store them at -70℃ or below, and thaw the froze vials as needed. We do know one freeze-thaw cycle will not affect its activity.

Q3. How do we recommend reconstituting the protein if the customer needs a higher concentration than the recommendation on the COA?

Please note that the solubility of the protein is influenced by other factors in the formulation (before lyophilization) as well including trehalose. Normally, the maximal concentration we can obtain is the concentration of the bulk solution before lyophilization. If the customers really must make a higher reconstitution concentration than what recommended in the COA, it is suggested to reconstitute the product with concentration no higher than the concentration of the bulk solution before lyophilization.

Q4. The function of the trehalose in the protein and the trehalose concentration in buffer.

1) Trehalose helps a lot to stabilize the protein solution and avoid any possible aggregation and precipitation, so we strongly recommend not to remove it, especially at higher protein concentration. In addition, trehalose will not interfere with primary amines or thiol related chemical reactions. If you really must use this protein without trehalose, for example used as analyte in SPR assays, we suggest you to run buffer exchange to get rid of trehalose immediate before use. There are many commercially available kits for this, such as Vivaspin ultrafiltration system. The products will be supplied in lyophilized form.

2)The bulk solution before lyophilization contains 10% trehalose as protectant. The trehalose concentration after recommended reconstitution varies from product to product and from lot to lot. But all relevant information will be provided to you on the lot-specific COA.

Q5. Can Arco provide the protein not be lyophilized nor have additives like trehalose or detergent?

Trehalose is strongly recommended to avoid protein activity loss during handling and storage. If you really must use this protein without trehalose, we suggest to run buffer exchange to get rid of trehalose immediate before use. There are many commercially available kits for this, such as Vivaspin ultrafiltration system.

Q6. The shelf life of the protein

The shelf life (based on the storage conditions indicated) published on the COA is from the date the customer actually received the product.

Q7. Are all the lyophilized proteins from ACRO sterile?

Yes, the finished proteins are usually lyophilized from bulk protein in a 0.2μm filtered solution, so they are sterile.

Q8. How do we calculate the concentration of the bulk solution before lyophilization for lot specific COA?

From the formulation part of lot-specific COA, we could know the volume of the bulk solution before lyophilization. Concentration=Size(ug/mg)/Volume(ul)

Q9. The information about Fc-fused proteins. (Fc tag may be from human Fc / mouse Fc / llama Fc).

All Fc-fused proteins will undergo Fc-mediated dimerization in solution. Some Fc-fusion proteins, depending on the structure of the protein itself, may further aggregate and form large polymers. The MW of the resulting protein species (dimer/trimer/polymer) may be reflected by the size of the band on a non-reducing SDS gel or SEC.

Q10. Does the endotoxin level of the bulk solution represent the endotoxin level of the lyophilization product?

The endotoxin level of the bulk solution can represent the endotoxin level of the lyophilization product. According to experience, the endotoxin detection value of the lyophilization product is 20-30% higher than that of the bulk solution (within the normal range, because the amount needs to be increased and the purity factor needs to be considered during lyophilization). Our freeze-drying process is strictly sterile and without heat source. So the endotoxin level of the bulk solution can basically represent the endotoxin level of the lyophilization product.

Q11. Are there carrier proteins in ARCO's proteins?

Most of the products of our company do not add carrier protein, and only a few products add BSA. It is suggested to refer to the buffer information on the product website.

Q12. Will the activity of protein be affected after being labeled?

Most biotinylated proteins from ACRO biosystems are built upon Avi tag single point site-specific biotinylating. In theory, adding any molecules/tags could potentially affect the natural state of the protein, and consequently its bioactivity. However, the biotin molecule and the Avi tag are both small, and inserted outside the target protein domain. Also, the DoL (Degree of labeling) is optimized for specific protein at ACRO biosystems to achieve highest detection sensitivity without compromise bioactivity. Therefore, it’s very unlikely that the normal protein activity will be affected by the labeling event. The bioactivity of all labeled proteins will be tested the binding to antibody or ligand by ELISA, FACS or cell-based assays.

Q13. Is there any free biotin in the biotinylated product?

Biotinylated products are desalinated to remove the free biotin, and if there is any residual biotin, it is only a small amount.

Q14. How to calculate the specific activity of protein products (cell-based assay)?

1. It’s recommended to input the ED50 which obtained in the cell-based assay experiment into the following link for conversion. https://www.biomol.com/resources/tools/cytokine-activity-conversion

2.The following formula can be brought in for calculation:

Q15.Does trehalose have effect on the cell-based assay?

The trehalose used by ACRO is injection grade and will be diluted during the experiment. In this case, trehalose should have no effect on the cells. We suggest that the buffer control group can be set up experimentally.

Q16 Why is most of Arco’s protein expressed from HEK293?

HEK293 cells also known as human embryonic kidney cells 293. The folding modification of HEK293 protein is closer to the form of real protein in human body. The folding modification of the protein expressed by HEK293 is closer to the form of real protein in human body, and most of the proteins we developed are targets or factors of human related diseases, so we chose HEK293 expression system

Q17. For integrin co-expression proteins, what is the function of Acidic Tail and Basic Tail?

Integrins are obligate heterodimers (alpha and beta chain), and the transmembrane helixes mediate the dimerization of alpha and beta chain. As the integrin product we developed is the extracellular domain, we need to introduce the Acidic/Basic tails to stabilize the heterodimers. It can promote the form of heterodimer to ensure forming the correct structure of integrin, which will not have bad effect on the protein activity.

Q18.How do you purify the His-tagged proteins?

We usually use IMAC (Immobilized Metal-ion affinity chromatography) to purify the His tagged proteins to high purity. The IMAC beads we used for production are from GE, Qiagen and other vendors.

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Contact Us

If you have more questions, please contact us at:

North America:
+1 800-810-0816 (Toll Free)
Asia & Pacific:
+86 400-682-2521

Q1. How can I get a quote and product availability?

To receive a quote and product availability, please contact us at order@acrobiosystems.com Please indicate the quantity and size of the product you want to purchase in your email. The quote with product availability will be sent to you within one business day.

Q2. Can I get a discount for bulk order?

We offer discount to those who make bulk purchases. For bulk inquiry, please contact us by email: order@acrobiosystems.com Please indicate the approximate quantity of the product you want to purchase or the future demand for this product in your email.

Q3. How do I place an order?

You can place an order online by creating an account in our official website (https://www.acrobiosystems.com), or send your purchase order to order@acrobiosystems.com , or fax it to 1-888-3776111 or even call us at 800-8100816, whichever is convenient for you. You can find more details here: How To Order - ACROBiosystems

Q4. Do you have distributors?

Yes, we have global distributors, if you would prefer to purchase from a local vendor, here are details for your reference: Distributors - ACROBiosystems

Q5. How can I know if my order is shipped or not?

We will send you the order confirmation including the tracking# or the estimated shipping date by email once the order is processed. You can also contact us at order@acrobiosystems.com to get the info you would like.

Q6. How much is the shipping cost and how long will I receive my package after it is shipped out?

The shipping cost and transit time will depend on the physical form of the product, the type of logistics service and the distance to the receiving address. You can find the detailed info here: Shipping and Payments - ACROBiosystems

Q7. What kind of payment method do you accept?

For online orders, we are pleased to accept PayPal, debit cards, and credit cards for orders placed at www.acrobiosystems.com. All transactions are confidential. We DO NOT keep customer credit card information.

For offline orders, we allow customers to make payments using a variety of methods including PayPal, debit or credit cards, paper check, and Electronic Fund Transfer (EFT). For more details, please see Payment Instruction. Shipping and Payments - ACROBiosystems

Q8. What circumstance need I to prepay for the order?

For 1st time buyer, we request full up-front payment before we make the shipment.

Q9. How can I set up NET30 payment terms with Acro?

If your company have credit reference sheet, please email (customerservice@acrobiosystems.com) to us, you are allowed to pay within 30 days after confirmation by our financial department.

If you don’t have credit reference sheet, please email (customerservice@acrobiosystems.com) us, and we will provide the Business Account Application Form for you.

Kindly remind that before applying for the payment terms, a full prepayment is required for the first time order from a valued new customer.

Q10. How can I cancel or change an order?

For online order, you can cancel it before making the payment. If you have paid and want to cancel it, please kindly contact us by email order@acrobiosystems.com or call us at +1 800-810-0816.

For offline order, please kindly contact us by email order@acrobiosystems.com

Q11. What if there is damage or short for the package I receive?

Firstly, please help to check the products and quantity carefully when you receive the package, if there are actual damages or short for the package, please take pictures immediately and contact us by order@acrobiosystems.com Then we will arrange the replacement or the refund to you.

Q12. Can I apply a sample before I place the bulk order?

If you would like to apply a sample, please help to send your company name, potential purchase amount to order@acrobiosystems.com, then our sales representative will evaluate and follow up. On the other hand, you can also pay attention to the promotion information on our website to check if there is sample application campaign.

Q13. What does Preorder means?

Preorder is not a formal order, which means that the product is still under development, but it can be ordered offline.

If you have not fully confirmed your purchase of this product, we recommend you to submit the preorder form in advance so that you can get the best spot on our internal scheduled production line. If you have confirmed to order this product, you can send the purchase order to order@acrobiosystems.com

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Contact Us

If you have more questions, please contact us at:

North America:
+1 800-810-0816 (Toll Free)
Asia & Pacific:
+86 400-682-2521
For queries related to invoice and remittance please contact: ar@acrobiosystems.com

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