Table 1

Specific activities for the β-elimination of l- andd-selenocysteine Se-conjugates and CTFE-cys in rat and human dialyzed kidney cytosol

No.	Compound	Rat Cytosol	Human Cytosol I	Human Cytosol II	Human Cytosol III
		nmol/min/mg protein
1	Se-ethyl-l-selenocysteine	16.84 ± 2.40	0.052 ± 0.002	0.070 ± 0.010	0.048 ± 0.001
2	Se-(n-propyl)-l-selenocysteine	17.17 ± 0.51	0.033 ± 0.003	0.038 ± 0.013	0.042 ± 0.016
3	Se-(n-butyl)-l-selenocysteine	13.62 ± 0.32	0.016 ± 0.001	0.018 ± 0.001	0.028 ± 0.006
4	Se-allyl-l-selenocysteine	10.30 ± 0.20	0.041 ± 0.001	0.057 ± 0.010	0.087 ± 0.002
5	Se-phenyl-l-selenocysteine	17.11 ± 1.58	0.224 ± 0.024	0.318 ± 0.015	0.252 ± 0.006
6	Se-(o-methylphenyl)-l-selenocysteine	17.79 ± 2.13	0.269 ± 0.018	0.318 ± 0.008	0.206 ± 0.035
7	Se-(o-chlorophenyl)-l-selenocysteine	13.81 ± 0.23	0.198 ± 0.016	0.255 ± 0.005	0.249 ± 0.020
8	Se-(o-methoxyphenyl)-l-selenocysteine	9.24 ± 0.53	0.052 ± 0.003	0.085 ± 0.001	0.101 ± 0.016
9	Se-(o-nitrophenyl)-l-selenocysteine	7.43 ± 0.69	0.144 ± 0.005	0.242 ± 0.042	0.344 ± 0.023
10	Se-(p-methylphenyl)-l-selenocysteine	5.61 ± 0.05	0.031 ± 0.001	0.047 ± 0.006	0.034 ± 0.002
11	Se-(p-methylphenyl)-d-selenocysteine	N.D.	0.015 ± 0.001	0.014 ± 0.004	0.029 ± 0.001
12	Se-(p-chlorophenyl)-l-selenocysteine	7.97 ± 0.23	0.073 ± 0.010	0.121 ± 0.009	0.188 ± 0.029
13	Se-(p-methoxyphenyl)-l-selenocysteine	12.45 ± 0.80	0.035 ± 0.004	0.066 ± 0.005	0.079 ± 0.011
14	Se-benzyl-l-selenocysteine	16.06 ± 0.24	0.026 ± 0.004	0.060 ± 0.008	0.089 ± 0.016
15	Se-(o-methylbenzyl)-l-selenocysteine	8.81 ± 0.16	0.056 ± 0.010	0.076 ± 0.018	0.082 ± 0.004
16	Se-(o-chlorobenzyl)-l-selenocysteine	15.49 ± 2.54	0.083 ± 0.002	0.147 ± 0.016	0.157 ± 0.008
17	Se-(o-nitrobenzyl)-l-selenocysteine	11.83 ± 0.85	0.055 ± 0.008	0.065 ± 0.009	0.097 ± 0.003
18	Se-(p-methylbenzyl)-l-selenocysteine	34.72 ± 1.73	0.193 ± 0.008	0.235 ± 0.009	0.180 ± 0.012
19	Se-(p-methylbenzyl)-d-selenocysteine	N.D.	N.D.	N.D.	0.007 ± 0.003
20	Se-(p-chlorobenzyl)-l-selenocysteine	28.81 ± 1.51	0.110 ± 0.008	0.182 ± 0.027	0.095 ± 0.008
21	Se-(p-methoxybenzyl)-l-selenocysteine	18.41 ± 0.13	0.044 ± 0.002	0.075 ± 0.017	0.043 ± 0.001
22	Se-(3,4-dichlorobenzyl)-l-selenocysteine	17.39 ± 0.37	0.061 ± 0.005	0.092 ± 0.011	0.072 ± 0.001
23	CTFE-cys	25.74 ± 2.20	0.162 ± 0.074	0.154 ± 0.024	0.068 ± 0.016

Substrates were incubated at a concentration of 1.4 mM in presence of 0.5 mM KMB and rat (0.3 mg/ml) or human (3.0–5.3 mg/ml) dialyzed kidney cytosol for 5 (rat) or 20 (human) min at 37°C. Results are presented as mean ± S.D. for three preparations.

N.D., activity could not be determined due to a low turnover of the enzyme.