Fmoc-12-amino-4,7,10-trioxadodecanoic acid

Fmoc-12-amino-4,7,10-trioxadodecanoic acid
Fmoc-NH-PEG3-CH2CH2COOH; 3-[2-[2-[2-(9H-fluoren-9-ylmethoxycarbonylamino)ethoxy]ethoxy]ethoxy]propanoic acid

Like its shorter counterpart this is not an amino acid: no α-carbon, no side chain, no stereocentre. It is an ethylene-glycol chain with an Fmoc-protected amine at one end and a free carboxylic acid at the other, which is what an Fmoc building block needs, so it is coupled and deprotected in the same steps as a residue.

What it contributes: between the amide nitrogen it brings and its own carbonyl carbon there are eleven atoms, three of them ether oxygens, and no substituents along the way. The acid end is a 3-alkoxypropanoic acid, with two carbons between the carbonyl and the nearest oxygen, where the shorter spacer has one. Fmoc-8-amino-3,6-dioxaoctanoic acid (47257) is the same kind of unit contributing seven atoms and two oxygens, and either can be coupled more than once to lengthen the spacer further.

What a spacer of this length does in a given construct has to be measured in that construct. What can be said here is structural: there is no stereocentre to epimerise on activation and no side-chain protecting group to remove at cleavage.

Applications

• Flexible spacer between a peptide and a label, biotin, chelator or other cargo
• Putting a longer, defined distance between two peptide segments
• Spacer series in which the length is varied one unit at a time

Storage
Store frozen, at or below -4 °C, in a tightly closed container, and let it reach room temperature before opening.

For research use only. Not for human or veterinary use.