Table 2. Specific activities of the recombinant ED enzymes of T. tenax and S. solfataricus.

Errors are given from three independent measurements. n.d., not detected.

Enzyme activity	Organism	Substrate concentration (mM)	Specific activity (units/mg)
GAD	T. tenax	10 mM gluconate	0.065±0.006
		10 mM galactonate	n.d.
KD(P)G aldolase	T. tenax	2 mM GA, 5 mM pyruvate	2.1±0.1
		2 mM GAP, 5 mM pyruvate	11.5±0.6
	S. solfataricus	2 mM GA, 5 mM pyruvate	2.2±0.2
		2 mM GAP, 5 mM pyruvate	5.8±0.7
KDG kinase	T. tenax	5 mM KDG, 2 mM ATP*	41.6±0.3
	S. solfataricus†	3 mM KDG*	0.104±0.001
GAPN	S. solfataricus†	3 mM GAP, 2 mM NADP+	3.36±0.08

* KDG was generated by KD(P)G aldolase and purified by anion-exchange chromatography.

† Protein fraction after heat precipitation.