Table 2.

Temperature optima, size, and methylated oligonucleotide inactivation of ATases

Strain	Size,* kDa	Optimum temp, °C		Inactivation by O6-methylguanine oligonucleotides, % of control
		Growth	ATase
S. acidocaldarius	16	78	≈75	91
Pyrococcus furiosus	22	100	≈100	94
P. islandicum	15	100	≈100	96
T. litoralis	23	88	≈90	94
E. coli BS21	39	37	37	34
Human	24	37	37	96

*As determined by polyacrylamide gel electrophoresis; see Fig. 3 and text.