The plasma membrane vesicles were purified from soybean (Glycine max L.) hypocotyls by two_phase partitioning methods. The stimulatory effects of K + on the coupling between ATP hydrolysis and proton transport by th...The plasma membrane vesicles were purified from soybean (Glycine max L.) hypocotyls by two_phase partitioning methods. The stimulatory effects of K + on the coupling between ATP hydrolysis and proton transport by the plasma membrane H +_ATPase were studied. The results showed that the proton transport activity was increased by 850% in the presence of 100 mmol/L KCl, while ATP hydrolytic activity was only increased by 28.2%. Kinetic studies showed that K m of ATP hydrolysis decreased from 1.14 to 0.7 mmol/L, while V max of ATP hydrolysis increased from 285.7 to 344.8 nmol Pi·mg -1 protein·min -1 in the presence of KCl. Experiments showed that the optimum pH was 6.5 and 6.0 in the presence and absence of KCl, respectively. Further studies revealed that K + could promote the inhibitory effects of hydroxylamines and vanadates on the ATP hydrolytic activity. The above results suggested that K + could regulate the coupling between ATP hydrolysis and proton transport of the plasma membrane H +_ATPase through modulating the structure and function of the kinase and phosphatase domains of the plasma membrane H +_ATPase.展开更多
The stimulatory effect of lysophosphatidylcholine (lyso_PC) on ATP and ρ_nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H +_ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Re...The stimulatory effect of lysophosphatidylcholine (lyso_PC) on ATP and ρ_nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H +_ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Results showed that lyso_PC stimulated the hydrolysis of ATP; ATP hydrolysis was enhanced dramatically when lyso_PC was within 0-0.03%, and increased slightly when lyso_PC was higher than 0.03%. At the concentration of 0.03%, lyso_PC stimulated ATP hydrolysis by 80.5%. Kinetics analysis showed that V max increased from 0.46 μmol P i·mg -1 protein·min -1 to 0.87 μmol P i·mg -1 protein·min -1 while K m increased from 0.88 mmol/L to 1.15 mmol/L under lyso_PC treatment. The optimum pH of ATP hydrolysis was shifted from 6.5 to 7.0 . Moreover, it was found lyso_PC enhanced the inhibition of ATP hydrolysis by hydroxylamine. In the presence of 200 mmol/L hydroxylamine, ATP hydrolysis was inhibited by 74.4%, while it was inhibited by 84.4% when treated with lyso_PC. However, PNPP hydrolysis and the inhibitory effect of vanadate were not affected by lyso_PC. The above results indicated that the kinase domain might be an action site or regulatory region of the C_terminal autoinhibitory domain in the plant plasma membrane H +_ATPase.展开更多
Seeds of soybeans and mung beans were soaked into five different concentrations （0, 0.05, 0.10, 0.20, 0.30 mg/L） of natural brassinolide （ NBR ） solution. According to the results, natural brassinolide treatment c...Seeds of soybeans and mung beans were soaked into five different concentrations （0, 0.05, 0.10, 0.20, 0.30 mg/L） of natural brassinolide （ NBR ） solution. According to the results, natural brassinolide treatment could improve seed germination rate and hypocotyl-radicle ratio of soybeans and mung beans and promote the growth of sprouts. To be specific, seed germination rate of soybeans reached the highest in 0.05 mg/L natural brassinolide treatment, which was im- proved by 25.0 percentage points compared with the control group, and the sprout length was improved by 4.33 em; 0.30 mg/L natural brassinolide exhibited the most significant promotion effect on seed germination and sprout growth of mung beans, seed germination rate was improved by 18.3 percentage points and sprout length was improved by 7.29 cm; hypocotyl-radiele ratio of soybean and mung bean sprouts reached the highest （2.96, 1.43 ） in 0.05 mg/L natural brassinolide treatment.展开更多
文摘The plasma membrane vesicles were purified from soybean (Glycine max L.) hypocotyls by two_phase partitioning methods. The stimulatory effects of K + on the coupling between ATP hydrolysis and proton transport by the plasma membrane H +_ATPase were studied. The results showed that the proton transport activity was increased by 850% in the presence of 100 mmol/L KCl, while ATP hydrolytic activity was only increased by 28.2%. Kinetic studies showed that K m of ATP hydrolysis decreased from 1.14 to 0.7 mmol/L, while V max of ATP hydrolysis increased from 285.7 to 344.8 nmol Pi·mg -1 protein·min -1 in the presence of KCl. Experiments showed that the optimum pH was 6.5 and 6.0 in the presence and absence of KCl, respectively. Further studies revealed that K + could promote the inhibitory effects of hydroxylamines and vanadates on the ATP hydrolytic activity. The above results suggested that K + could regulate the coupling between ATP hydrolysis and proton transport of the plasma membrane H +_ATPase through modulating the structure and function of the kinase and phosphatase domains of the plasma membrane H +_ATPase.
文摘The stimulatory effect of lysophosphatidylcholine (lyso_PC) on ATP and ρ_nitrophenyl phosphate (PNPP) hydrolysis by the plasma membrane H +_ATPase from soybean (Glycine max (L.) Merr.) hypocotyls was studied. Results showed that lyso_PC stimulated the hydrolysis of ATP; ATP hydrolysis was enhanced dramatically when lyso_PC was within 0-0.03%, and increased slightly when lyso_PC was higher than 0.03%. At the concentration of 0.03%, lyso_PC stimulated ATP hydrolysis by 80.5%. Kinetics analysis showed that V max increased from 0.46 μmol P i·mg -1 protein·min -1 to 0.87 μmol P i·mg -1 protein·min -1 while K m increased from 0.88 mmol/L to 1.15 mmol/L under lyso_PC treatment. The optimum pH of ATP hydrolysis was shifted from 6.5 to 7.0 . Moreover, it was found lyso_PC enhanced the inhibition of ATP hydrolysis by hydroxylamine. In the presence of 200 mmol/L hydroxylamine, ATP hydrolysis was inhibited by 74.4%, while it was inhibited by 84.4% when treated with lyso_PC. However, PNPP hydrolysis and the inhibitory effect of vanadate were not affected by lyso_PC. The above results indicated that the kinase domain might be an action site or regulatory region of the C_terminal autoinhibitory domain in the plant plasma membrane H +_ATPase.
基金Supported by Key Joint Foundation for Fostering Talents of NSFC-Henan Province(U1204307)Key Project of Science and Technology of Henan Province(102102110155,142102110173,152102210334)Cultivation Fund of Luoyang Normal University(2013-PYJJ-001,10000993)
文摘Seeds of soybeans and mung beans were soaked into five different concentrations （0, 0.05, 0.10, 0.20, 0.30 mg/L） of natural brassinolide （ NBR ） solution. According to the results, natural brassinolide treatment could improve seed germination rate and hypocotyl-radicle ratio of soybeans and mung beans and promote the growth of sprouts. To be specific, seed germination rate of soybeans reached the highest in 0.05 mg/L natural brassinolide treatment, which was im- proved by 25.0 percentage points compared with the control group, and the sprout length was improved by 4.33 em; 0.30 mg/L natural brassinolide exhibited the most significant promotion effect on seed germination and sprout growth of mung beans, seed germination rate was improved by 18.3 percentage points and sprout length was improved by 7.29 cm; hypocotyl-radiele ratio of soybean and mung bean sprouts reached the highest （2.96, 1.43 ） in 0.05 mg/L natural brassinolide treatment.
