TABLE 1.

Deamination of PSI-6130 and PSI-6130-MP^a

Enzyme	Substrate	kcat (s−1)	Km (μM)	kcat/Km (μM−1 s−1)
CDA	Cytidine	5.4 ± 0.3	40 ± 5	0.14
	2′-Deoxycytidine	4.8 ± 0.2	41 ± 4	0.12
	2′-F-2′-deoxycytidine	3.8 ± 0.4	27 ± 8	0.14
	2′-C-Methylcytidineb	0.18 ± 0.02	3,100 ± 600	0.000058
	PSI-6130b	0.26 ± 0.02	4,000 ± 500	0.000065
DCTD	DCMP	246 ± 16	87 ± 22	2.8
	PSI-6130-MP	0.82 ± 0.07	2,000 ± 300	0.0004

^aAll values were determined by spectrophotometric assay, except that an HPLC assay was used for the DCTD reactions with PSI-6130-MP.

^bThe highest concentration tested was 4 mM.