Lipoamido-dPEG®12-acid, product number 10808, is a PEG-based crosslinking and surface modification reagent. The lipoamide moiety rapidly forms stable dative bonds with gold. Using a carbodiimide such as EDC and an acylating agent such N-hydroxysuccinimide (NHS), the propionic acid group will react with free amines to form amide bonds. The water-soluble, non-immunogenic dPEG® spacer adds hydrodynamic volume to conjugates made with this product. The increased hydrodynamic volume reduces the renal clearance of the conjugated molecules.

Lipoic Acid

Lipoic acid, also known as thioctic acid and alpha-lipoic acid (ALA), is an organosulfur compound used by cells as an essential cofactor for several enzymes in aerobic respiration. The sulfur atoms at positions C6 and C8 form a disulfide bond in a five (5)-membered ring.

Like other thiol products, lipoic acid readily forms dative bonds with gold, silver, and other metals. Because two dative bonds form for each molecule of lipoic acid, the thiol-metal dative bond is more stable than dative bonds formed with compounds containing one free thiol atom. For a brief, clear explanation of dative bonds, please see chapter 3 in Bioconjugate Techniques, 3rd edition.[1]

Lipoic acid exists typically in an oxidized (closed ring) state. It is readily reduced to an open ring state using tris(2-carboxyethyl)phosphine (TCEP). This reduced form is known as dihydrolipoic acid (DHLA). Quanta BioDesign makes and sells TCEP as product number 10014.

PEGylation with dPEG® Products

Quanta BioDesign’s single molecular weight dPEG® products are different from traditional PEGylation reagents. Whereas conventional, disperse polymer PEGylation reagents contain a complex mixture of different chain lengths, and molecular weights of PEG, Quanta BioDesign’s products consist of a single, discrete length chain of PEG of uniform molecular weight. Quanta BioDesign’s dPEG® products provide all of the benefits of traditional PEGylation reagents without the headaches that these disperse polymer PEGylation reagents cause. For a thorough discussion of our dPEG® technology, please visit our “What is dPEG®?” page. For answers to our most frequently asked questions, please visit our “Frequently Asked Questions (about dPEG® products)” page.

Using Lipoamido-dPEG®12-acid

Lipoamido-dPEG®12-acid is designed to form crosslinks between gold surfaces and free amines on biomolecules such as proteins and peptides. The lipoic acid end of the molecule reacts with gold first, followed by the activation of the carboxylic acid group and coupling to free amines. Reducing the lipoic acid end of the molecule to DHLA with TCEP frequently occurs before reacting the lipoic acid with the gold surface.

Bulk Scale Synthesis of Lipoamido-dPEG®24-acid is Available

If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.

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Lipoamido-dPEG®24-acid is a water-soluble crosslinker between gold and free amines on biomolecules. The single molecular weight dPEG® spacer has no dispersity.

Hydrophobic crosslinkers create more problems than they solve. Traditional disperse polymer PEGylation reagents add unnecessary analytical complexity to conjugates that incorporate them.

Stop using inferior products!

Start using single molecular weight dPEG® products and discover the dPEG® difference. To get started, please click the “Add to Cart” button now to order Lipoamido-dPEG®12-acid, product number 10808.

Application References:

[1] Hermanson, G. T. Chapter 3, The Reactions of Bioconjugation. In Bioconjugate Techniques; Academic Press: New York, NY, 2013; pp 229–258. Many scientists engaged in bioconjugation work consider Greg Hermanson’s book to be the definitive technical reference on the subject. Click here now to read a review of Greg’s book and to purchase it.

Additional information

Weight .5 oz
Dimensions .75 × .75 × 2 in