Table 6.

Substrate activity of various MeP prodrugs with M64V PNP

Compound	wild-type	M64V	M64V/wt
	nmoles/mg-hr
9-β-D-ribofuranosyl-6-methylpurine (MeP-R)	84,000	176,000	2
9-(2-deoxy-β-D-ribofuranosyl)-6-methylpurine (MeP-dR)	528,000	593,000	1
9-(α-L-lyxofuranosyl)-MeP	218	10,200	47
9-(5-deoxy-α-L-lyxofuranosyl)-MeP	20	3,500	175
9-(6-deoxy-β-D-allofuranosyl)-6-methylpurine	47	316	7
9-(6-deoxy-α-L-talofuranosyl)-6-methylpurine (5’-methyl (talo) MeP-R)	1,440	86,000	60
9-(2,6-dideoxy-β-D-talofuranosyl)-6-methylpurine	3,600	264,000	73
9-(5,5-dimethyl-β-D-ribofuranosyl)-6-methylpurine	-	280	>280
F-dAdo	435,000	1,595,000	4
9-β-D-arabinofuranosyl-2-F-adenine (F-araA)	1,250	1,000	1
9-α-L-lyxofuranosyl-2-F-adenine	7,800	244,000	31
9-(6-deoxy-β-D-allofuranosyl)-2-F-adenine	2,700	92,000	34
9-(6-deoxy-β-D-talofuranosyl)-2-F-adenine (5’-methyl (talo) F-Ado)	34,000	1,360,000	40

Enzymes were incubated with 100 µM of each substrate and the rate of cleavage was determined by HPLC separation of the base form the nucleoside. Each value is the average of at least two experiments that were in good agreement.