. 2003 Jun 2;22(11):2583–2592. doi: 10.1093/emboj/cdg275

Table IV. Comparison of wild-type and mutant LEH enzymes.

Residue	Replaced with	Growth	Expression level (% of total protein)	[NaCl] (mM) needed to elute from ion-exchange column	k_cat (s^–1)	K_m (mM)	k_cat/K_m (s^–1M^–1)
WT	–	Normal	20–40	210	0.470	1.4	340
Tyr53	Phe	Normal	20–40	210	0.170	3.7	46
Asn55	Ala	Normal	20–40	215	0.002	1.4	1.64
Asn55	Asp	Normal	20–40	580	ND	ND	ND
Arg99	Ala	Slow	3–10	560	ND	ND	ND
Arg99	Lys	Slow	3–10	530	ND	ND	ND
Arg99	Gln	Slow	3–10	500	ND	ND	ND
Arg99	His	Slow	3–10	545	ND	ND	ND
Asp101	Ala	Normal	20–40	170	ND	ND	ND
Asp101	Asn	Normal	20–40	215	ND	ND	ND
Asp132	Ala	Normal	20–40	455	ND	ND	ND
Asp132	Asn	Normal	20–40	195	ND	ND	ND
Asn55/Asp132	Asp/Asn	Normal	20–40	240/480^a	ND	ND	ND

Mutants that showed any measurable activity in an initial assay with 60 µM of racemic styrene-7,8-oxide were characterized further.

ND, not detectable. The threshold of detectable activity was ∼0.1% of that of the wild-type enzyme.

^aTwo peaks were observed for this mutant.