TABLE 2.

Activities of purine salvage and interconversion enzymes and purine uptake in H. volcanii and H. halobium^a

Purine	Activity (nmol/min/mg of protein) in:
	H. volcanii	H. halobium
Salvage and interconversion enzymes
Adenine deaminase	<0.01	<0.01
Adenosine deaminase	0.12 ± 0.02	0.76 ± 0.19
AMP deaminase	<0.02	<0.02
Guanine deaminase	1.14 ± 0.27	0.53 ± 0.12
Adenosine phosphorylase	2.63 ± 0.52	0.10 ± 0.02
Guanosine phosphorylase	5.42 ± 0.51	0.37 ± 0.04
Inosine phosphorylase	3.74 ± 0.19	2.89 ± 0.14
Adenosine kinase	<0.01	<0.01
Guanosine kinase	0.12 ± 0.03	0.06 ± 0.02
Inosine kinase	0.12 ± 0.02	0.05 ± 0.01
Adenine phosphoribosyltransferase	1.43 ± 0.12	2.05 ± 0.17
Guanine phosphoribosyltransferase	2.45 ± 0.23	0.87 ± 0.17
Hypoxanthine phosphoribosyltransferase	2.13 ± 0.18	2.34 ± 0.21
Xanthine phosphoribosyltransferase	<0.01	<0.01
Xanthine oxidase	<0.01	<0.01
Adenylosuccinate synthetase	0.72 ± 0.04	0.56 ± 0.03
Adenylosuccinate lyase	0.02 ± 0.003	0.04 ± 0.004
Uptake
Adenine	0.31 ± 0.03	0.65 ± 0.06
Guanine	0.23 ± 0.04	0.19 ± 0.04
Hypoxanthine	0.25 ± 0.07	0.40 ± 0.04
Adenosine	0.13 ± 0.03	0.44 ± 0.03
Guanosine	0.09 ± 0.03	0.63 ± 0.04
Inosine	0.14 ± 0.02	0.48 ± 0.03

^aCells were grown in liquid medium and were analyzed as described in Materials and Methods. Values are means of at least two experiments ± standard deviations.