. Author manuscript; available in PMC: 2018 Apr 13.

Published in final edited form as: Nat Commun. 2015 Jun 22;6:7300. doi: 10.1038/ncomms8300

Table 1.

Kinetic parameters for primer synthesis.

Primase	k_cat (min⁻¹)	K_m (μM)	k_cat/K_m (μM⁻¹ min⁻¹)
rNTP
PriSL	ND^*	ND^*	14.3 × 10⁻⁴^†
PriSX	0.66 ± 0.13^‡	14.1 ± 3.4	0.047
PriSLX	1.31 ± 0.09	3.2 ± 0.75	0.409
dNTP
PriSL	ND^*	ND^*	0.77 × 10⁻⁴^†
PriSX	ND^§	8.75 ± 0.6	ND^§
PriSLX	1.01 ± 0.07	5.42 ± 1.1	0.186

dNTP, deoxynucleoside triphosphate; rNTP, ribonucleoside triphosphate; ND, not determined.

These parameters were not determined (ND) because the velocity of reaction increased linearly with an increasing substrate concentration under the assay conditions.

^†

The k_cat/K_m values for PriSL are calculated based on the equation: v/[E]_o = k_cat[dNTP]/{K_m + [dNTP]} = (k_cat/K_m) [dNTP] when K_m is much larger than [dNTP].

^‡

s.e.m., n = 3.

^§

These parameters were not determined because of the interference of substrate inhibition (K_i: 244.8 ± 8.6 μM).