Polyamino Acids: Frequently Asked Questions

Q1: What is a polyamino acid?

A polyamino acid, sometimes also called polypeptide, is a synthetic biopolymer made from amino acid repeating units, i.e. -[NH-CHR-CO]x-.

Q2: What are the main applications of polyamino acids?

Polyamino acids are used in various medical and biological applications such:
- cell adhesion
- drug delivery
- gene therapy
- diagnostic
- oncology
- antibacterial
- antifungal
- surface chemistry

Q3: Which process is used to synthesize polyamino acids?

Polypeptides are obtained by the ring-opening polymerization of alpha-amino acid N-carboxyanhydrides (NCAs).

Q4: Why is Alamanda's polymerization technique uniquely better?

Our process is superior for several reasons:
- total control over the molecular weight (i.e. chain length) and the composition (for copolymers)
- low polydispersity index (PDI=1.01-1.2)
- no use of metal catalyst, i.e. metal-free polymer

Q5: Why are low polydispersity index and control over the molecular weight important for you?

The polydispersity index (PDI) is a measure of the molecular weight distribution in the polymer. A PDI close to 1 results in polymers with uniform chain length. The control over the molecular weight allows to obtain the exact chain length that you expect. Consequently, our polyamino acids could increase the efficiency of your experiments and save you money by determining the most accurate chain length and composition you need.

Q6: Which methods are used to purify Alamanda's polyamino acids?

Typically, polyamino acids are purified after polymerization by precipitation in water or in an organic nonsolvent and, after amino acid side chain deprotection, by dialysis. All water-soluble polymers are finally lyophilized.

Q7: Can Alamanda Polymers provide batch to batch consistency?

Absolutely. The low polydispersity index and control over the molecular weight obtained with our polymerization process produces almost the same polyamino acids from lot to lot.

Q8: How long have Alamanda's polymerists been synthesizing polyamino acids?

We have been working on NCA polymerization and especially on poly-L-lysine since 1999.

Q9: Which methods are used to analyze Alamanda's polyamino acids?

The Polydispersity index is measured either on the protected polyamino acids by gel permeation chromatography (GPC) in DMF with 0.1M LiBr at 60°C or on the deprotected polypeptides by GPC in aqueous buffer using, in both cases, a calibration curve that was constructed from narrow polydispersity PEG standards or universal calibration of TALLS. The average molecular weight is provided by TALLS or by proton NMR spectroscopy using the amino acid repeating unit to incorporated initiator peaks integration ratio.

Q10: Which counterion do I choose with poly-L-lysine derivatives?

If you don't work in gene therapy, you can choose the least expensive poly-L-lysine derivatives, i.e. trifluoroacetate. No difference has been reported in terms of chemical reactivity. Also, all poly-L-lysine trifluoroacetate chain lengths (PLKF) are soluble in polar organic solvents such DMF, DMSO, NMP or DMA. If you work with DNA and RNA, we strongly advise using chlorinated poly-L-lysine derivatives since differences between trifluoroacetate, hydrobromide, and hydrochloride polymers have been described in the literature.

Q11: What should I do if my chain length or polyamino acid is not in the catalog?

We can do contract or collaborative custom-synthesis. Please feel free to contact us or at 1-877-alpoly-7 and explain your request. We will answer as soon as possible.

Q12: How do I place an order?

If your country is listed, you can directly place an order on our website. Otherwise, please fax your order to us at 256-489-4529.

Q13: How do you ship your products?

We ship all of our polymers at room temperature. Delivery in the U.S. is estimated at 1-2 days from the date of shipment, and most international shipments arrive within 5 days.

Q14: What are the handling conditions for polyamino acids?

As all our polyamino acids are hygroscopic, a dry room with the least possible humidity level should be used to quickly weigh or handle the polymers. We also strongly recommend sonicating the polyamino acids for 10 minutes after their solubilization, just before using them, in order to remove any aggregates.

Q15: What are the storage conditions for polyamino acids?

We recommend storing all polyamino acids dry, below -15°C, and under an inert atmosphere.