Protective effect of taurine on hypochlorous acid toxicity to nuclear nucleoside triphosphatase in isolated nuclei from rat liver

Table 1 Effects of taurine on hepatic nuclear NTPase activity

Groups	NTPase activity (nmol/mg Pr per 10 min)
	ATP as substrate	GTP as substrate
Control	127 ± 7	150 ± 9
Taurine 10-6 mol/L	136 ± 9 (+7.1%)	168 ± 10 (+ 12.0%)a
Taurine 10-5 mol/L	148 ± 7 (+16.5%)b	179 ± 11 (+19.3%)b
Taurine 10-4 mol/L	150 ± 8 (+18.1%)b	191+12 (+27.3%)b

ATP and GTP were used as reaction substrates, respectively. The increases of the enzyme activities are indicated in paren-theses as percentage of the control. Mean ± SD, n = 6.

^aP < 0.05,

^bP < 0.01 compared with control.

Table 2 Effect of taurine and glutathione on ^·OH -induced inhibition of NTPase activity in hepatic nuclei

Groups	NTPase activity (nmol/mg Pr per 10 min)
	ATP as substrate	GTP as substrate
Control	100.0 ± 9.9	151.8 ± 9.9
Tau (10-4 mol/L)	138 ± 14.6	175.5 ± 5.9
GSH (10-4 mol/L)	95 ± 12.2	150.0 ± 9.8
OH	29.8 ± 8.2b	35.3 ± 7.8b
OH+Tau (10-6 mol/L)	35.6 ± 6.1	36.2 ± 8.8
OH+Tau (10-5 mol/L)	40.8 ± 8.8	32.7 ± 7.3
OH+Tau (10-4 mol/L)	46.5 ± 8.7a	43.3 ± 7.2
OH+GSH (10-6 mol/L)	32.0 ± 8.2	43.2 ± 11.8
OH+GSH (10-5 mol/L)	32.1 ± 9.7	41.2 ± 9.6
OH+GSH (10-4 mol/L)	44.3 ± 6.2	39.8 ± 5.9

ATP and GTP were used as reaction substrates, respectively. ^·OH was produced by Fenton chemistry (Fe³⁺-H₂O_2: 1 mmol/L/ 5 µmol/L). Mean ± SD, n = 6. Tau: taurine, GSH: glutathione.

^bP < 0.01 compared with control group (OCl^-1 10^-6 mol·L^-1).

^aP < 0.05 compared with ^·OH (Fe³⁺-H₂O_2: 1 mmol/L/5 µmol/L) group.