. Author manuscript; available in PMC: 2020 Nov 1.

Published in final edited form as: Pigment Cell Melanoma Res. 2019 Jun 3;32(6):753–765. doi: 10.1111/pcmr.12791

Table 2.

Kinetic parameters of TYRtr measured in excess TYRP1tr.

	pH 7.2		pH 5.5
	TYRtr	1:20	TYRtr	1:20
K_m (mM)	1.01 ± 0.18	0.53 ± 0.45	0.72 ± 0.11	0.30 ± 0.39
V_max (nmole/min)	0.16 ± 0.01	0.13 ± 0.02	0.08 ± 0.01	0.10 ± 0.02
k_cat (min⁻¹)	3.20 ± 0.20	2.60 ± 0.40	1.60 ± 0.20	2.00 ± 0.40
k_cat/K_m (min⁻¹/mM)	3.17 ± 1.11	4.91 ± 0.87	2.22 ± 2.00	6.67 ± 1.03

K_m, Michaelis-Menten constant defining the affinity of L-DOPA for TYRtr, and V_max, the rate at which a L-DOPA is converted to dopachrome once bound to the TYRtr, were calculated from Michaelis-Menten plots fitted with the corresponding nonlinear function using OriginPro 2018b software; k_cat is the enzyme turnover, i.e., the number of L-DOPA molecules turned over per TYRtr molecule per minute, and was defined to equal V_max/E_t, where E_t is the TYRtr concentration (0.05 nM); k_cat/K_m, enzyme efficiency.