Alcaligenes bronchisepticus

Biocatalytk decarboxylation is a imique reaction, in the sense that it can be considered to be a protonation reaction to a carbanion equivalent intermediate in aqueous medimn. Thus, if optically active compoimds can be prepared via this type of reaction, it would be a very characteristic biotransformation, as compared to ordinary organic reactions. An enzyme isolated from a specific strain of Alcaligenes bronchisepticus catalyzes the asymmetric decarboxylation of a-aryl-a-methyhnalonic acid to give optically active a-arylpropionic acids. The effect of additives revealed that this enzyme requires no biotin, no co-enzyme A, and no ATP, as ordinary decarboxylases and transcarboxylases do. Studies on inhibitors of this enzyme and spectroscopic analysis made it clear that the Cys residue plays an essential role in the present reaction. The imique reaction mechanism based on these results and kinetic data in its support are presented. 

Alcaligenes bronchisepticus KU 1201 decarboxylates a-methyl-a-phenylmalonic acid to form (l )-a-phenylpropanoic acid. 

K. Miyamoto and H. Ohta, "Asymmetric decarboxylation of disubstituted malonic acid by Alcaligenes bronchisepticus KU1201", Biocatalysis 5, 49-60 (1991). 

Figure 1 Compounds that are inactive to Alcaligenes bronchisepticus.

The low yield and/or optical purity achieved with the previous methodologies, as well as the possibility to stabilize the cells by immobilization, has opened the possibility of biotransformations using whole cells. In this way, aryhnalonic acids were transformed into 2-arylpropionic acids by incubation with Alcaligenes bronchisepticus [60]. 

---