2-keto-3-deoxy-6-phospho-D-galactonate

Comparable to the situation for the sialic acid and KDO lyases (vide supra), sets of stereochemically complementary pyruvate lyases are known, e,g. in Pseudomonas strains, which act on related 2-keto-3-deoxy-aldonic acids [112]. The enzymes cleaving six-carbon sugar acid phosphates—the KdgA and 2-keto-3-deoxy-6-phospho-D-galactonate (20) aldolases (KDPGal aldolase EC 4.1.2.21) [139] — are typified as class I enzymes, whereas those acting on non-phosphorylated five-carbon substrates — 2-keto-3-deoxy-L-arabonate (21) (KDAra aldolase EC 4.1.2,18) [140, 141] and 2-keto-3-deoxy-D-xylonate (22)... 

Aldol reactions catalyzed in vivo by the 2-keto-3-deoxy-6-phospho-D-gluconate and 2-keto-3-deoxy-6-phospho-D-galactonate aldolases. 

Stereocomplementary sets of pyravate dependent aldolases. /V-acetyIneuraminic acid aldolase (NeuA EC 4.1.3.3), 2-keto-3-deoxy-manno-octosonate (KDO) aldolase (KdoA EC 4.1.2.23), 2-keto-3-deoxy-6-phospho-D-gluconate aldolases (GIcA EC 4.1.2.14)) and 2-keto-3-deoxy-6-phospho-D-galactonate aldolases (GalA EC4.1.2.21). 

The 2-keto-3-deoxy-aldonic acid (phosphate) aldolases from Pseudomonas strains - 3-deoxy-2-keto-L-arabonate (F.C 4.1.2.18), 3-deoxy-2-keto-D-xylonate (EC 4.1.2.28), 3-deoxy-2-keto-6-phospho-D-gluconate (EC 4.1.2.14) and 3-deoxy-2-keto-6-phospho-D-galactonate aldolase (EC 4.1.2.21) - appear to be specific even for the acceptor components, but allow stereoselective syntheses of the respective natural substrates29. 

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