The tobacco RuBPcase was purified by the method of (NH 4) 2SO 4 precipitation and Sephadex G 200 column chromatography. The effects of Ln 3+ on inhibition of RuBPcase activity were studied. The results show t...The tobacco RuBPcase was purified by the method of (NH 4) 2SO 4 precipitation and Sephadex G 200 column chromatography. The effects of Ln 3+ on inhibition of RuBPcase activity were studied. The results show that the v max (maximum velocity) of RuBPcase does not change, but its k m (Michaelis constant) increases with a k i (inhibitor constant) when increasing the concentration of Ln 3+ in enzymatic reaction. It indicates that the inhibitory action of Ln 3+ on tobacco RuBPcase is a model of competitive inhibition with Mg 2+ . The k i of La 3+ , Ce 3+ and Gd 3+ is 26 3, 34 3 and 200 μmol·L -1 , respectively. Their inhibitory action on the RuBPcase is in the order of La 3+ >Ce 3+ Gd 3+ .展开更多
The effects of La3+ on total activity and initial activity of RuBPCase (ribulose 1,5-hisphosphate carboxylase) in tobacco seedlings were studied. When treated with 20 similar to 80 mu mol.L-1 LaCl3 in Hoagland solutio...The effects of La3+ on total activity and initial activity of RuBPCase (ribulose 1,5-hisphosphate carboxylase) in tobacco seedlings were studied. When treated with 20 similar to 80 mu mol.L-1 LaCl3 in Hoagland solution by water culture, the activities of RuBPCase were raised, and the activation action of LaCl3 on initial activity was higher than that on total activity. But when the concentration of LaCl3 surpassed 80 mu mol.L-1, the activities of RuBPCase were inhibited. It was also found that La3+ and Ce3+ can replace Mg2+ to activate the activity of RuBPCase in the enzymatic reaction, and the activation actions of La3+ and Ce3+ on the purified enzyme are higher than those on crude enzyme. The results indicate that La3+ activates the activity of RuBPCase in vivo as well as in vitro.展开更多
文摘The tobacco RuBPcase was purified by the method of (NH 4) 2SO 4 precipitation and Sephadex G 200 column chromatography. The effects of Ln 3+ on inhibition of RuBPcase activity were studied. The results show that the v max (maximum velocity) of RuBPcase does not change, but its k m (Michaelis constant) increases with a k i (inhibitor constant) when increasing the concentration of Ln 3+ in enzymatic reaction. It indicates that the inhibitory action of Ln 3+ on tobacco RuBPcase is a model of competitive inhibition with Mg 2+ . The k i of La 3+ , Ce 3+ and Gd 3+ is 26 3, 34 3 and 200 μmol·L -1 , respectively. Their inhibitory action on the RuBPcase is in the order of La 3+ >Ce 3+ Gd 3+ .
文摘The effects of La3+ on total activity and initial activity of RuBPCase (ribulose 1,5-hisphosphate carboxylase) in tobacco seedlings were studied. When treated with 20 similar to 80 mu mol.L-1 LaCl3 in Hoagland solution by water culture, the activities of RuBPCase were raised, and the activation action of LaCl3 on initial activity was higher than that on total activity. But when the concentration of LaCl3 surpassed 80 mu mol.L-1, the activities of RuBPCase were inhibited. It was also found that La3+ and Ce3+ can replace Mg2+ to activate the activity of RuBPCase in the enzymatic reaction, and the activation actions of La3+ and Ce3+ on the purified enzyme are higher than those on crude enzyme. The results indicate that La3+ activates the activity of RuBPCase in vivo as well as in vitro.