Frequently Asked Questions

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General

Can we receive discounts on rPeptide products?
You may be eligible for a discount when placing a bulk order. Please contact us to request a quotation before placing your order.
Can you label a purified peptide that I provide?
Unfortunately, it would not be an option for us to label purified proteins that you provide. The labeling of the protein has to occur as the protein is being produced; we give it 15N nitrogen source. If you would be interested in having us produce a labeled peptide or if you have any further questions please let us know.
How can I achieve batch to batch consistency of Physical and Chemical Properties?
Due to the fact that our beta-amyloids are recombinantly produced, there is a batch to batch consistency in the physical and chemical properties of all our recombinant beta-amyloid peptides.
How can I find rPeptide's citations?
You may find rPeptide's citations under the Publications tab. Citations are listed by Product, then by year.
How can your products be used?
Our products are not for human use, they are for research purposes only.
How may I request a price quotation for a custom product?
You may email the quantity, purity and sequence you would like to info@rpeptide.com.
What if I cannot find the answer to my question online?
Please feel free to email us at techsupport@rpeptide.com for other inquires.
Why does solubility vary from product to product?
The key factor that determines the solubility of our products is the amino acid sequence of each one. In the preparation of our products, we analyze the amino acid sequences and prepare our products in buffers that they solubilize in readily.
Why must some products ship on dry ice?
Some products must be stored at -70°C and therefore cannot ship at room temperature. To maintain the integrity of the product, it will ship on dry ice. Additional charges will apply for dry ice shipments.

Ordering

How can I place an order?
You can send your order by Fax (678-753-0746) or call and place the order by phone (678-753-0747) or do it on line http://www.rpeptide.com/ordering.php. When placing an order please give us the following information. Company’s , University’s or Institute’s Name Contact Person’s Name(Attn: to) Phone No. Fax No. e-mail Address Purchase Order No. Credit Card No. Ship To Address Bill To Address VAT No. if needed Quotation No. if needed
How do you ship products?
Domestic orders are shipped FedEx Standard Overnight. International orders ship using FedEx International Priority.
How long does it take to receive the products?
Domestic orders are shipped FedEx Standard Overnight. International orders ship using FedEx International Priority. A tracking number will be provided to you so that you may monitor your package.
What is the cost of shipping on dry ice?
In addition to regular shipping charges, dry ice charges are $25 for Domestic orders, and $45 for International.
What is the cost of shipping?
Domestic orders are shipped FedEx Standard Overnight for $40. International orders (including Canada) ship using FedEx International Priority for $85. Additional charges may apply if dry ice is required.

Beta Amyloids

How can your Beta Amyloids be used?
Our products are not for human use, they are for research purposes only.
How pure are your recombinant beta-amyloid peptides?
The purity of our recombinant beta-amyloid peptides is consistently >97%. The salt content is ca. 10% of the total weight. The peptide amount specified is the net peptide content. The peptide quantities are estimated by HPLC against a calibration curve derived from quantities estimated by amino acid analyses.
How should your Beta Amyloid be stored after reconstitution in ammonium hydroxide?
After reconstitution in ammonium hydroxide, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks.or longer term, its best to lyophilize it.
How should your lyophilized Beta Amyloid be stored?
The lyophilized Beta Amyloid can be stored for at least 2 years at -80°C.
I see you use HPLC to check purity. When you say it is >97%, is it strictly based on the peak area of the target peak?
Purity is determined by the ratio of the Beta Amyloid peak area against the total peak area of all the peak areas combined
What does HFIP stand for?
HFIP is Hexafluoroisopropanol
What is the solubility of your recombinant Beta Amyloids?
Beta-amyloid peptides: Resuspend in 1 % NH4OH, at a concentration of 1 mg/ml. Sonicate for 30 seconds after it has gone into solution. The Beta-Amyloid, NaOH salts (A-1155 and A-1165, http://www.rpeptide.com/products/products_7.html) can be resuspended in water.
What is the stability of your lyophilized Beta Amyloid?
The lyophilized Beta Amyloid is stable for at least 2 years at -80°C. After reconstitution in ammonium hydroxide, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks.or longer term, its best to lyophilize it.
When you state that this vial contains 0.5 mg of peptide, is that precisely weighted or is it possible that there is an excess peptide? When we reconstitute the peptide and dose it by its absorbance at 280 nm, we get much more peptide than expected (more than 200%). Is this normal?
The peptide amount is calibrated chromatographically against known amounts of the product as determined by amino acid analysis. In our experience absorption at 280 nm is extremely low and hence we do not check either the purity or quantitate at 280nm.

Taus

Do you run mass specs for Taus or only gel?
Purity assay for tau is done by SDS only, no mass spec.
Do your Tau Proteins have his tags?
Our Tau proteins do not have his tags. Advantage of Tau proteins without his tag vs tau proteins with his tag: 1. Tau protein with his-tag is more likely to be insoluble and hence inamenable for various biochemical assays. This problem will not be there in the Tau protein without any tag. 2. Tau protein with his-tag is more likely to have contaminating proteins which will be coming due to the non-specific nature of interaction between polyhistidine tags and Ni2+ ions. These proteins will interfere with any of the assays or functions of Tau proteins. 3. There are chances that some Nickel too can come as contaminant which can severely alter the functions of Tau. 4. A his-tag Tau can also be immunogenic if used in humans. There can be immune response against the polyhistidine tag which has the potential to act as a linear epitope.
How can your Taus be used?
Our products are not for human use, they are for research purposes only.
How should your lyophilized Tau be stored?
The lyophilized Tau can be stored for at least 2 years at -80°C.
How should your Tau be stored after reconstitution in water?
After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.
What is the stability of lyophilized Taus?
The lyophilized Tau is stable for at least 2 years at -80°C. After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.
Which one of the Tau protein isoforms that you sale is the longest or which ones are the most phosphorylated?
Tau 441 is the biggest tau that we have. Since they are made in E.coli they are not phosphorylated.

Synucleins

How can your Synucleins be used?
Our products are not for human use, they are for research purposes only.
How should your lyophilized Synuclein be stored?
The lyophilized Synuclein can be stored for at least 2 years at -80°C.
How should your Synuclein be stored after reconstitution in water?
After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.
I wonder whether during the E. coli expression and protein purification of your synuclein products, a compound called "trifluoroacetate", is involved in any of the steps?
Trifluoroacetate is not used during any of the steps in the synuclein purification.
Regarding Alpha Synuclein: Is the protein full length? Is it tagged, if so, with what?
The Alpha Synuclein is full length and has no tag.
What is the stability of lyophilized Synucleins?
The lyophilized Synuclein is stable for at least 2 years at -80°C. After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.

Antibodies

How can your antibodies be used?
Our products are not for human use, they are for research purposes only.

Other

How can your products be used?
Our products are not for human use, they are for research purposes only.

Beta Amyloids • Stability

How should your Beta Amyloid be stored after reconstitution in ammonium hydroxide?
After reconstitution in ammonium hydroxide, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks.or longer term, its best to lyophilize it.
How should your lyophilized Beta Amyloid be stored?
The lyophilized Beta Amyloid can be stored for at least 2 years at -80°C.
What is the stability of your lyophilized Beta Amyloid?
The lyophilized Beta Amyloid is stable for at least 2 years at -80°C. After reconstitution in ammonium hydroxide, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks.or longer term, its best to lyophilize it.

Taus • Stability

How should your lyophilized Tau be stored?
The lyophilized Tau can be stored for at least 2 years at -80°C.
How should your Tau be stored after reconstitution in water?
After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.
What is the stability of lyophilized Taus?
The lyophilized Tau is stable for at least 2 years at -80°C. After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.

Synucleins • Stability

How should your lyophilized Synuclein be stored?
The lyophilized Synuclein can be stored for at least 2 years at -80°C.
How should your Synucleins be stored after reconstitution in water?
After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.
What is the stability of lyophilized Synucleins?
The lyophilized Synuclein is stable for at least 2 years at -80°C. After reconstitution in water, its best to aliquot it (AVOID FREEZE THAW) and store at -80°C. This should be stable for about 1-2 weeks. For longer term, its best to lyophilize it.