A STARCH DEFICIENT MUTANT OF ARABIDOPSIS-THALIANA WITH LOW ADPGLUCOSE PYROPHOSPHORYLASE ACTIVITY LACKS ONE OF THE 2 SUBUNITS OF THE ENZYME
A STARCH DEFICIENT MUTANT OF ARABIDOPSIS-THALIANA WITH LOW ADPGLUCOSE PYROPHOSPHORYLASE ACTIVITY LACKS ONE OF THE 2 SUBUNITS OF THE ENZYME
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DOI：
10.1104/pp.88.4.1175
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发表时间：
1988-12-01
期刊：
影响因子：
7.4
通讯作者：
PREISS, J
中科院分区：
文献类型：
--
作者：
LIN, TP;CASPAR, T;PREISS, J
拟南芥（Arabidopsis thaliana（L.）Heynh，其中叶提取物含有的ADP葡萄糖焦磷酸化酶（EC 2.7.7.27）活性仅为野生型的约5%。一个单一的，在以前未描述的基因座命名为adg2的核突变是负责突变表型。虽然突变体含有的ADP葡萄糖焦磷酸化酶活性只有野生型的5%，但在12小时光周期中生长时，它积累的淀粉是野生型的40%。 在连续光照下生长时，突变体也含有野生型淀粉的约40%，这表明合成速率调节其稳态积累。使用抗菠菜54和51千道尔顿（kD）ADP葡萄糖焦磷酸化酶亚基的抗体对叶提取物进行免疫学分析表明，突变体缺乏交叉反应性54 kD多肽，并且只有野生型的交叉反应性51 kD多肽的约45倍。这一结果和遗传学研究表明，adg 2是编码54 kD多肽的结构基因，并提供了第一个功能证据，表明54 kD多肽是天然ADP葡萄糖焦磷酸化酶的必需组分。
A starch deficient mutant of Arabidopsis thaliana (L.) Heynh, has been isolated in which leaf extracts contain only about 5% as much activity of ADPglucose pyrophosphorylase (EC 2.7.7.27) as the wild type. A single, nuclear mutation at a previously undescribed locus designated adg2 is responsible for the mutant phenotype. Although the mutant contained only 5% as much ADPglucose pyrophosphorylase activity as the wild type, it accumulated 40% as much starch when grown in a 12 hour photoperiod. The mutant also contained about 40% as much starch as the wild type when grown in continuous light, suggesting that the rate of synthesis regulates its steady state accumulation. Immunological analysis of leaf extracts using antibodies against the spinach 54 and 51 kilodaltons (kD) ADPglucose pyrophosphorylase subunits indicated that the mutant is deficient in a cross-reactive 54 kD polypeptide and has only about 45 as much as the wild type of a cross-reactive 51 kD polypeptide. This result and genetic studies suggested that adg2 is a structural gene which codes for the 54 kD polypeptide, and provides the first functional evidence that the 54 kd polypeptide is a required component of the native ADPglucose pyrophosphorylase enzyme.