Enzymatic improvement of mitochondrial thiol oxidase Erv1 for oxidized glutathione fermentation by Saccharomyces cerevisiae

Table 1 Kinetic and thermal profiles of Erv1 and its variants

Protein	Maximum temperature (°C)^a	T _1/2 (°C)^b	K _m (mM)^c	V _max (mU)^c	K _cat (min⁻¹)^c
Erv1	60	<90	4.4	2.1	0.05
Erv1^S32A	60	69.3	13.0	5.4	0.12
Erv1^S32T	60	68.8	12.0	4.4	0.10
Erv1^N34A	55	64.1	33.5	11.6	0.25
Erv1^S32A/N34A	55	59.1	40.5	15.9	0.42
Erv1^S32T/N34A	55	62.0	41.2	9.1	0.20

^aThe enzymes were assayed at each temperature and pH 7.0 for 10 min with 10 mM GSH as the substrate
^bThe temperature at which the residual activity equaled 50%. The enzymes were incubated at each temperature and subsequently assayed at 30 °C and pH 7.0 for 10 min with 10 mM GSH as the substrate
^cThe enzymes were assayed at 30 °C and pH 7.0 for 10 min with various concentrations of GSH as the substrate

ISSN: 1475-2859