Steady-state kinetics of catecholamine transport by chromaffin-granule "ghosts".
Steady-state kinetics of catecholamine transport by chromaffin-granule "ghosts".
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嗜铬颗粒“幽灵”转运儿茶酚胺的稳态动力学。
DOI：
10.1042/bj1440319
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发表时间：
1974
期刊：
影响因子：
--
通讯作者：
J. Phillips
中科院分区：
文献类型：
--
作者：
J. Phillips
用重封的嗜铬粒和鬼粒研究了儿茶酚胺转运的稳态动力学。该泵对（-）-去甲肾上腺素、（-）-肾上腺素、酪胺和5-羟色胺（血清素）具有高亲和力，但对（+）-去甲肾上腺素具有较低亲和力。测得的掺入速率不符合Michaelis-Menten动力学，但前底物的亲和常数在8- 18 μ m范围内。利血平是一种有效的抑制剂。作为ATP浓度的函数的掺入也不能显示简单的动力学;在1 mm-MgCl（2）下，ATP的亲和常数推断为约3 mm。腺苷酰（β-γ-亚甲基）二膦酸酯在低浓度下是竞争性抑制剂，但在高浓度下抑制更强。该泵的转变温度为29 ℃，似乎与嗜铬颗粒的Mg（2+）刺激的腺苷三磷酸酶不相同。
Resealed chromaffin-granule ;ghosts' were used to study the steady-state kinetics of catecholamine transport. The pump has a high affinity for (-)-noradrenaline, (-)-adrenaline, tyramine and 5-hydroxytryptamine (serotonin), but a lower affinity for (+)-noradrenaline. The measured rates of incorporation do not conform to Michaelis-Menten kinetics, but affinity constants for the former substrates are in the range 8-18mum. Reserpine is a potent inhibitor. Incorporation as a function of ATP concentration also fails to show simple kinetics; the affinity constant for ATP is deduced to be about 3mm at 1mm-MgCl(2). Adenylyl (betagamma-methylene)diphosphonate is a competitive inhibitor at low concentrations, but inhibits more strongly at high concentrations. The pump has a transition temperature at 29 degrees C and does not seem to be identical with the Mg(2+)-stimulated adenosine triphosphatase of chromaffin granules.