TABLE 6.

Enantioselectivity of toluene cis-dihydrodiol dehydrogenase^a

Substrateb	μmol of NADH produced/μmol of substratec
	TDD (F1)	TDD (E. coli)
(+)-Biphenyl cis-2,3-dihydrodiol	1.09 ± 0.02	0.94 ± 0.01
(−)-Biphenyl cis-2,3-dihydrodiol	0.07 ± 0.01	0.08 ± 0.01
50:50 (±)-biphenyl cis-2,3-dihydrodiol	0.51 ± 0.01	0.44 ± 0.01
70:30 (±)-biphenyl cis-3,4-dihydrodiol	0.73 ± 0.06	0.65 ± 0.03

^aReactions were initiated by the addition of 0.1 to 0.3 μmol of the substrates indicated. The amount of NADH was measured at 340 nm (biphenyl cis-3,4-dihydrodiol) or 350 nm (biphenyl cis-2,3-dihydrodiol) until no further increase in absorbance was observed. 

^b(+)-Biphenyl cis-2,3-dihydrodiol (>99% enantiomeric purity) was generated by S. yanoikuyae B8/36; (−)-biphenyl cis-2,3-dihydrodiol (>95% enantiomeric purity) was generated by P. stutzeri C250; 50:50 (±)-biphenyl cis-2,3-dihydrodiol was a mixture of the above two substrates; 70:30 (±)-biphenyl cis-3,4-dihydrodiol was generated by the F352L mutant of NDO. 

^cTDD (F1), toluene cis-dihydrodiol dehydrogenase partially purified from P. putida F1; TDD (E. coli), toluene cis-dihydrodiol dehydrogenase in extracts from a recombinant E. coli strain expressing the todD gene. Values are means and standard deviations for three separate experiments.