Table I.

Kinetic parameters of barley (HvNTR1, HvNTR2) and Arabidopsis (AtNTR) NTR for barley Trx h isoforms (HvTrxh1, HvTrxh2) and E. coli Trx

Enzyme	Substrate	Km	kcat	kcat/Km
		μm	s−1	s−1m−1
pH 7.4
HvNTR1	HvTrxh1	1.18 ± 0.25	2.25 ± 0.08	1.90 × 106
HvNTR1	HvTrxh2	1.79 ± 0.40	1.31 ± 0.08	0.73 × 106
HvNTR2	HvTrxh1	1.12 ± 0.04	3.26 ± 0.09	2.91 × 106
HvNTR2	HvTrxh2	1.29 ± 0.25	2.98 ± 0.16	2.31 × 106
HvNTR2	E. coli Trx	107	1.6	1.55 × 104
AtNTR	HvTrxh1	24.70 ± 5.00	1.04 ± 0.09	0.42 × 105
AtNTR	HvTrxh2	26.70 ± 6.50	0.80 ± 0.07	0.30 × 105
pH 5.7
HvNTR1	HvTrxh2	1.45	0.43	0.30 × 106
HvNTR2	HvTrxh2	0.90	0.8	0.89 × 106