Aberer W, Kostron H, Huber E, Winkler H
Biochem J. 1978 Jun 15;172(3):353-60. doi: 10.1042/bj1720353b.
Chromaffin granules isolated from bovine adrenal gland were incubated with (3)H-labelled nucleotides and [(14)C]noradrenaline to study the uptake of these substances. [(3)H]ATP, [(3)H]ADP and [(3)H]AMP are taken up by these organelles by the same temperature-dependent mechanism. The apparent K(m) for ATP and ADP is 1.4mm, and for AMP it is 2.9mm. The uptake of ATP has a flat pH optimum, whereas the catecholamine uptake increases with more alkaline pH. Atractyloside and carboxyatractyloside are competitive and specific inhibitors of nucleotide uptake, whereas reserpine inhibits only that for catecholamines. Mg(2+) ions activate uptake of both catecholamine and nucleotides, whereas EDTA and N-ethylmaleimide inhibit these processes. Nucleotide and catecholamine uptakes are inhibited by uncouplers of oxidative phosphorylation and by two ATP analogues. NH(4) (+) ions and nigericin in the presence of KCl inhibit only catecholamine uptake. It is concluded that nucleotide uptake, as proposed previously for catecholamine uptake, depends on an electrochemical proton gradient produced by a proton-translocating adenosine triphosphatase localized in the membrane of chromaffin granules. Furthermore, as suggested by the effect of NH(4) (+) and nigericin, catecholamine uptake apparently depends on the chemical part of this gradient, whereas the results for nucleotide uptake are consistent with its dependence on the electrical component.
从牛肾上腺分离出的嗜铬颗粒与³H标记的核苷酸和[¹⁴C]去甲肾上腺素一起孵育，以研究这些物质的摄取情况。[³H]ATP、[³H]ADP和[³H]AMP通过相同的温度依赖性机制被这些细胞器摄取。ATP和ADP的表观米氏常数（K(m)）为1.4mmol/L，AMP的表观米氏常数为2.9mmol/L。ATP的摄取具有平坦的最适pH值，而儿茶酚胺的摄取随着pH值更碱性而增加。苍术苷和羧基苍术苷是核苷酸摄取的竞争性特异性抑制剂，而利血平仅抑制儿茶酚胺的摄取。镁离子激活儿茶酚胺和核苷酸的摄取，而乙二胺四乙酸（EDTA）和N-乙基马来酰亚胺抑制这些过程。核苷酸和儿茶酚胺的摄取受到氧化磷酸化解偶联剂和两种ATP类似物的抑制。在氯化钾存在下，铵离子和尼日利亚菌素仅抑制儿茶酚胺的摄取。得出的结论是，如先前对儿茶酚胺摄取所提出的那样，核苷酸摄取取决于位于嗜铬颗粒膜中的质子转运三磷酸腺苷酶产生的电化学质子梯度。此外，正如铵离子和尼日利亚菌素的作用所表明的那样，儿茶酚胺摄取显然取决于该梯度的化学部分，而核苷酸摄取的结果与其对电成分的依赖性一致。
