Aspartate family scheme

The decarboxylase family of enzymes catalyzes the PLP-dependent removal of CO2 from substrates. This reaction has found great industrial utility with one specific enzyme in particular, L-aspartate-P-decarboxylase (EC 4.1.1.12) from Pseudomonas dacunhae. This enzyme, most often used as immobilized whole cells, has been used to synthesize L-alanine on an industrial scale (multitons) since the mid-1960s by Tanabe (Scheme 28) [159,173]. Another use for this biocatalyst has been the resolution of racemic aspartic acid to produce L-alanine and D-aspartic acid (Scheme 29). 

Figure 18. Biosynthetic pathways for amino acids in the aspartate family. Circled Ps represent phosphate groups, POs. Pj represents inorganic phosphate, HPO/. [H] indicates reduction. T indicates transamination. Branch points and likely sites of isotopic fractionation are discussed in the text. In this and other reaction schemes, filled and open circles mark positions enriched or depleted in as a result of the source of the carbon flowing to that position. Upward and downward arrows mark positions likely to be enriched or depleted in C relative to precursor positions as a result of fractionations induced by isotope...

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