Aspartase and

This enzyme [EC 4.3.1.1], also known as aspartase and fumaric aminase, catalyzes the conversion of aspartate to fumarate and ammonia. 

Figure 25. Trace enantiomer analysis of L-aspartic acid (obtained by enzymatic amination of fumarate with L-aspartase and determined as the A -trifluoroacetyl-O-methyl ester) on i.-Chirasil-Val31 [20 mx0.25 mm (i.d.) glass capillary column, 90 CC, 0.4 bar hydrogen] with detection by GLC MS selected ion monitoring (mj 198.1) and multiscanning chromatography (MSC, 8 scans)186.

Extracts of various microbial species, such as Bacillus cadaveris or Proteus vulgaris, catalyze the condensation of fumaric (but not maleic) acid and hydroxylamine (37). These organisms are rich in aspartase and the enzyme is regarded as responsible for the reaction. The product was a... 

There have been a number of excellent reviews on L-aspartate production [2-4] that have focused on the immobilization of the key enzyme, aspartase, and productivity of the immobilized biocatalyst. The aspartase enzyme has only been given cursory consideration with regard to its importance to the overall efficiency of the L-aspartic acid process. This chapter reviews some of the ways in which better aspartase biocatalysts have been produced. 

M. Terasawa, S. Nara, H. Yamagata, H. Yu-gawa, Manufacture of d-Aspartic Acid and/or L-Malic Acid with Aspartase and Fumarase, Mitsubishi Petrochemical Co., 1991, JP06014787. 

L-Aspartate is produced by a one-step enzymatic method from fumarate and ammonia and by a two-step method from maleate via fumarate. The conversion of fumarate to L-aspartate is catalyzed by aspartase and maleate to fumarate by maleate isomerase ... 

Scheme 2.214 Amination of fumarate derivatives by aspartase and 3-methylaspartase...

Ti-Aspartic Oxidase. Aspartase and transaminases account for a major part of the metabolism of L-aspartic acid. n-Aspartic acid is oxidized by an enzyme present in liver and kidney. This is an oxidase that converts aspartate to oxalacetate and ammonia while reducing oxygen to hydrogen peroxide. The oxidase was resolved by ammonium sulfate precipitation and dialysis to a protein that could be reactivated by FAD but not by FMN. The enzyme differs from n-amino acid oxidase in its insensitivity to benzoate. The only other known substrate for the partially purified D-aspartic oxidase is D-glutamate, but since the relative rates of oxidation of the two amino acids vary during the preparation of the enzyme, it is... 

Microorganisms and some plant tissues are capable of catalyzing a multiplicity of nonoxidative amino acid deamination reactions. It is beyond the scope of this chapter to review these systems, since for the most part they have not been studied with cell-free preparations. Two exceptions to the latter statement are the aspartase and tryptophanase systems. The latter is discussed in the chapter, Carbon Catabolism of Amino Acids. 

Fumarate salts can be enzymatically converted to L-aspartate and to L-malate by aspartase and fumarase, respectively. The industrial processes for these versatile products have been described by Liese et al. (2006). 

Chao, Y.P., Lob, T.E., Luoa, N.S., 2000. Selective production of L-aspartic acid and L-phenylalanine by coupling reactions of aspartase and aminotransferase in Escherichia coU. Enzyme and Miaobial Technology 27,19-25. 

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