Table 2. HEWT evolution toward small cyclic ketones. Turnover frequencies (TOF) measured at 10 mM carbonyl concentration, molar conversions (m.c.), and enantiomeric excess (e.e.) for wild-type HEWT and isolated variants towards tetrahydrothiophen-3-one (3a) tetrahydrofuran-3-one (4a), 1-methylpyrrolidin-3-one (5a) and 1-methyl-piperidin-3-one (6a). Final conversion was obtained within 2 hours of reaction ^a .

Substrate	WT			C1
	TOF (10–3 s–1)	m.c. (%)	e.e. (%)	TOF (10–3 s–1)	m.c. (%)	e.e. (%)
	206 ± 5	>99	66 (S)	460 ± 6	>99	66 (S)
	430 ± 1	>99	70 (S)	580 ± 3	>99	70 (S)
	18 ± 0.2	94	90 (S)	11.6 ± 0.3	94	90 (S)
	10 ± 0.8	98	90 (S)	19 ± 0.8	98	90 (S)

^aBiotransformation reactions were performed with 10 mM ketones, 10 mM (S)-1-phenylethylamine, 0.1 mM PLP, 1 mg mL^–1 (19 µM) enzyme in 50 mM phosphate buffer pH 8 and 10% (v/v) DMSO at 37 °C (see Experimental in the ESI, Fig. S10). All experiments were conducted in triplicate and the standard error is reported accordingly. Mutation in C1: D5E.