Maciaga Marcin, Paszkowski Andrzej
Department of Biochemistry, Faculty of Agriculture and Biology, Warsaw Agricultural University, Nowoursynowska 159/37, 02-776 Warszawa, Poland.
J Appl Genet. 2004;45(4):411-7.
Zymograms of the aspartate aminotransferase (AAT, EC 2.6.1.1) activity in leaf extracts from Aegilops and Triticum species revealed three AAT zones, denoted according to the decreasing electrophoretic mobility towards the anode as AAT-1, AAT-2 and AAT-3. The AAT activity zymograms of subcellular fractions isolated from T. aestivum seedlings made it possible to establish that the AAT-1 zone is located in the mitochondria, AAT-2 in the chloroplasts and AAT-3 in the cytoplasm. Most of the total AAT activity from wheat leaves arises from the chloroplasts and cytoplasm. The AAT-3 zone exhibited the lowest electrophoretic mobility, but 3 isoenzymes occurring within were the most visibly separated. The occurrence of a single band in this zone at the AAT-3a position (closest to the anode) for the aneuploid CS3ASDt AABBDD line (the absence of long arms of the 3rd pair of homologous chromosomes in the A genome) and at the AAT-3c position for Ae. umbellulata (genome UU), as well as three bands in the whole zone for T. durum (AABB) and T. aestivum (AABBDD) each, made it possible to evaluate the subunit composition of isoenzymes in the AAT-3 zone. The band at the AAT-3a position in the zymogram is formed from bb dimers, AAT-3b from ab and AAT-3c from aa. By comparing the distribution of isoenzyme bands intensities (the result of enzymatic activity) with the mathematical models, the frequencies of the occurrence of the a and b subunits within AAT-3 zone were evaluated. In AAT-3 from T. durum, a and b occurred at the ratio of 0.54:0.46, and in that from T. aestivum - 0.62:0.38, respectively.
对山羊草属和小麦属植物叶片提取物中的天冬氨酸转氨酶（AAT，EC 2.6.1.1）活性进行酶谱分析，结果显示有三个AAT区，根据它们向阳极移动的电泳迁移率递减，分别标记为AAT-1、AAT-2和AAT-3。从小麦幼苗中分离得到的亚细胞组分的AAT活性酶谱表明，AAT-1区位于线粒体中，AAT-2区位于叶绿体中，AAT-3区位于细胞质中。小麦叶片中大部分的AAT总活性来自叶绿体和细胞质。AAT-3区的电泳迁移率最低，但该区域内出现的3种同工酶分离得最为明显。非整倍体CS3ASDt AABBDD品系（A基因组中第3对同源染色体的长臂缺失）在AAT-3区的AAT-3a位置（最靠近阳极）出现一条带，伞形山羊草（基因组UU）在AAT-3c位置出现一条带，而硬粒小麦（AABB）和普通小麦（AABBDD）在整个区域均出现三条带，这使得评估AAT-3区同工酶的亚基组成成为可能。酶谱中AAT-3a位置的条带由bb二聚体形成，AAT-3b由ab形成，AAT-3c由aa形成。通过将同工酶条带强度分布（酶活性结果）与数学模型进行比较，评估了AAT-3区内a和b亚基出现的频率。在硬粒小麦的AAT-3中，a和b的出现比例分别为0.54:0.46，在普通小麦的AAT-3中，a和b的出现比例分别为0.62:0.38。
