. Author manuscript; available in PMC: 2021 Jun 1.

Published in final edited form as: J Struct Biol. 2020 Apr 10;210(3):107506. doi: 10.1016/j.jsb.2020.107506

Table 3.

BtSpeG kinetic parameters calculated from substrate saturations curves for different polyamines. All reactions were performed for 5 min at 37°C and enzyme was preincubated with polyamine prior to performing kinetics. Parameters were calculated from fitting the Michaelis Menten equation to data as described in Materials and Methods.

Substrate	K_M (mM)		k_cat (s⁻¹)		k_cat/K_M (M⁻¹s⁻¹)

Spermine^a	0.162	± 0.011	153	± 3	9.46×10⁵
Spermidine^a	0.127	± 0.008	70.6	± 1.2	5.57×10⁵

Data were collected from 0–4 mM polyamine but only data from 0–2 mM are plotted and fitted because curves reached complete saturation at concentrations of polyamines less than 4 mM. No substrate inhibition was observed at higher concentrations of polyamine.