N-Tris(hydroxymethyl)methyl-2-aminoethanesulfonic Acid

White/clear crystalline powder

A structural analog to Tris buffer.

N-Tris(hydroxymethyl)methyl-2-aminoethanesulfonic Acid (TES) probably exists in solution as a zwitterion. Because the pKa is 7.4 (physiological pH) this buffer has considerable potential for a variety of biological applications. A buffer using TES free acid can be prepared by titrating the free acid (sc-206102) with sodium hydroxide to the desired pH, using about a half-equivalent of NaOH. Alternatively, solutions of equimolar TES free acid and TES sodium (sc-264384) can be mixed to attain a buffer of the desired pH.  It has been shown to be toxic in vitro, but this toxicity may be due to its ability to form metal chelate complexes that are toxic for cells. TES is a commonly used biological buffering agent.

ChEBI: N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid is a Good's buffer substance, pKa = 7.5 at 20 ℃. It is a member of ethanolamines, an amino sulfonic acid and a TES. It is functionally related to a taurine. It is a tautomer of a N-tris(hydroxymethyl)methyl-2-ammonioethanesulfonate.

Crystallise the acid from hot EtOH containing a little water.