NOTOPHOSPHORYLATION BY SWISS-CHARD CHLOROPLASTS
NOTOPHOSPHORYLATION BY SWISS-CHARD CHLOROPLASTS
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DOI：
10.1016/0006-3002(60)91350-0
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发表时间：
1960-01-01
期刊：
影响因子：
--
通讯作者：
AVRON, M
中科院分区：
文献类型：
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作者：
AVRON, M
本文报道了甜菜叶绿体和叶绿体片段的制备方法，它们具有磷酸化活性。可以获得稳定24-48小时的叶绿体制剂。采用灵敏的ATP形成测定法。它允许测量非常少量的ATP形成，并避免了在其他测定中遇到的一些困难。研究了对反应介质和反应混合物的要求。研究的因素包括抗坏血酸，气相，pH值，辅因子，镁，磷酸盐，核苷酸特异性和光强度。叶绿体能以高速率磷酸化ADP、GDP或IDP，以低速率磷酸化UDP，而CDP根本不能。证明了制剂中的核苷二磷酸激酶。没有腺苷酸激酶活性可以发现在洗涤或破碎的瑞士甜菜叶绿体。在包括低叶绿体浓度、短反应时间、适当抗坏血酸浓度和非常高的光强度（约150，000勒克斯）的最佳条件下，获得了2000-2500吉摩尔ATP形成/mg叶绿素/h的速率。证实了2，4-二硝基苯酚的无效性和铵离子作为解偶联剂的有效性，以及在甜菜叶绿体中无机磷酸盐和ATP之间缺乏交换。ADP和ATP之间没有交换。
The preparation of chloroplasts and chloroplast fragments from swiss-chard, which were active in photophosphorylation is described. A chloroplast preparation stable for 24-48 hours could be obtained. A sensitive assay for the ATP formed was adopted. It allowed the measurement of very small amounts of ATP formed, and avoided several difficulties encountered in other assays. The requirements in the homogenizing medium and in the reaction mixture were studied. Factors studied included ascorbate, gas phase, pH, cofactors, magnesium, phosphate, nucleotide specificity and light intensity. The chloroplasts could phosphorylate ADP, GDP, or IDP at high rates, UDP at low rates, and CDP not at all. Nucleoside diphosphokinase(s) in the preparations was demonstrated. No adenyl kinase activity could be found in washed or fragmented swiss-chard chloroplasts. Rates of 2000-2500 jimoles ATP formed/mg chlorophyll/h were obtained under optimal conditions, which included low chloroplast concentrations, short reaction times, appropriate ascorbate concentration, and very high light intensities (approximately 150,000 lux). Confirmation was presented for the ineffectiveness) of 2,4-dinitrophenol and effectiveness of ammonium ions as uncoupling agents, and the lack of exchange between inorganic phosphate and ATP in swiss-chard chloroplasts. No exchange between ADP and ATP could be demonstrated.