Aspartic acid acylase

Aspartame is synthesized using the L enantiomer of phenylalanine. The L enantiomer is separated from the D enantiomer, the racemic mixture, by reacting it with acetic anhydride (CH3C0)20) and sodium hydroxide. The product of this reaction is then treated with the enzyme porcine kidney acylase. An organic extraction with acid yields the L enantiomer in the aqueous layer and the D enantiomer in the organic layer. The L-phenylalanine is reacted with methanol and hydrochloric acid to esterify the COOH group on phenylalanine. The esterified L-phenyalanine is then reacted with aspartic acid, while using other chemicals to prevent unwanted side reactions, to produce aspartame. 

Recently a number of enzymatic systems have been developed at several chemical companies including Upases (synthesis of enantiotrope alcohols, R-amid, S-amin), nitrilases (R-mandehc acid), amidases (non-proteinogenic L-amino acids), aspartic acid ammonia lyase (L-aspartic add), penicilin acylase (6-Aminopenicilanic acid), acylases (semisynthetic penicillins), etc.( Koeller and Wong, 2001 and references therin). 

Apart from acylase I, another aminoacylase was found in kidney preparations by fractionation of hog kidney homogenates with ammonium sulfate and acetone1131. Whereas acylase I could be enriched and thus partially purified by this procedure the main activity with N-acylated-L-aspartic acid as the substrate was found in another... 

Two D-aminoacylases have been described that resemble the L-specific acylase II from kidney, which only hydrolyzes the N-acyl derivatives of L-aspartic acid. The d-specific counterpart of acylase II, N-acetyl-D-aspartate deacetylase, has been isolated from Alcaligenes xylosoxydans subsp. xylosoxydans,n The same strain produces an aminoacylase which specifically hydrolyzes N-acyl derivatives of D-glutamic acid131L The latter N-acetyl-D-glutamate deacetylase has also been found in Pseudomonas sp. 33. ... 

Aminoacridine monohydrochloride. See 9-Aminoacridine hydrochloride Aminoacylase. See Acylase S(+)-2-Amino-5-[(aminoiminomethyl) amino] pentanoic acid. See Arginine aspartate Aminoamylene glycol. See Aminoethyl propanediol... 

---