Inactive enzymatic mutant proteins (phosphoglycerate mutase and enolase) as sugar binders for ribulose-1,5-bisphosphate regeneration reactors

Table 1 The binding constants of proteins for sugar metabolites.

Protein	Condition	3-Phosphoglycerate		3-Phosphoglyceraldehyde
			Kd (μm)		Kd (μm)
PGDM	10 mM Tris-Cl pH 7.5, 50 mM NaCl	+++	655 ± 33	++	822 ± 42
	10 mM Tris-Cl pH 4.0, 50 mM NaCl	R		R
Enolase, S39A	10 mM Tris-Cl pH 7.5, 10 mM NaCl, 10 mM MgCl₂	+++	676 ± 28	++	835 ± 38
	10 mM Tris-Cl pH 7.5, 10 mM NaCl, 1 mM MgCl₂, 15 mM EDTA	R		R
Enolase, H159A	10 mM Tris-Cl pH 7.5, 10 mM NaCl, 10 mM MgCl₂	++	796 ± 23	+	966 ± 31
	10 mM Tris-Cl pH 7.5, 10 mM NaCl, 1 mM MgCl₂, 15 mM EDTA	R		R

The binding constant was estimated from scatchard type plots using experimental data. The results provided here are from 3 replicates ± standard deviations. The substrates used in different concentration were analyzed with respect to BSA control for binding using TLC as described in methods. A silver nitrate protocol was used for detection and spot area determination. Plus signs denote the strength of ligandbinding; R indicates ligand release.

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