. 2005 Jun;14(6):1538–1544. doi: 10.1110/ps.051393805

Table 1.

Biochemical parameters of ribonuclease A and its variants

Ribonuclease	pI^a	Tm^b (°C)	k_cat/K_M^c (10⁶M⁻¹s⁻¹)	IC₅₀^d (μM)
RNase A	8.6	63.7	1.8 ± 0.2	>25
RNase A-R9	9.6	56	1.0 ± 0.2	>25
G88RNase A	8.8	60	12.6 ± 0.4	5.8 ± 1.0
G88R RNase A-R9	9.8	54.0	9.6 ± 0.2	2.0 ± 0.4

^a Values of pI were estimated from amino acid composition (Bjellqvist et al. 1993, 1994).

^b Values of T_m (±1°C) were determined in PBS by UV spectroscopy.

^c Values of k_cat/K_M(±SE) are for the catalysis of 6-FAM-dArU(dA)₂–6-TAMRA cleavage at 25°C in 10 mM Bis-Tris-HCl buffer, pH 6.0, containing NaCl (0.50 M).

^d Values of IC₅₀ (±SE) are for the incorporation of [methyl-³H]thymidine into the DNA of K-562 cells.