. 2021 May 14;60(21):1682–1698. doi: 10.1021/acs.biochem.0c00944

Table 1. SAMHD1 Catalytic Parameters for dNTP and R_p-dNTPαS Nucleotides.

substrate	AL1 activator	AL2 activator	K_M (μM)	h^a	k_cat (s^–1)
dATP	GTP	dATP	44 ± 3		0.40 ± 0.01^b
dGTP	GTP/dGTP	dGTP	24 ± 2		0.27 ± 0.02
TTP	GTP	TTP	75 ± 6		0.48 ± 0.04
dCTP	GTP	dCTP	151 ± 6	1.4 ± 0.1	0.40 ± 0.01
R_p-dATPαS	GTP	R_p-dATPαS	53 ± 2		0.23 ± 0.01
R_p-dGTPαS	GTP/R_p-dGTPαS	R_p-dGTPαS	10 ± 0.5		0.09 ± 0.01
R_p-TTPαS	GTP	R_p-TTPαS	38 ± 4		0.26 ± 0.01
R_p-dCTPαS	GTP	R_p-dCTPαS	54 ± 4	2.0 ± 0.2	0.12 ± 0.01

For GTP/dCTP and GTP/R_p-dCTPαS, K_M is derived from a Hill equation V = (V_max[S]^h)/(K_M^h + [S]^h) where h is the Hill coefficient for substrate binding;

Error is the SEM of at least three independent measurements.

Table 1. SAMHD1 Catalytic Parameters for dNTP and Rp-dNTPαS Nucleotides.

Table 1. SAMHD1 Catalytic Parameters for dNTP and R_p-dNTPαS Nucleotides.