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The study of phosphoenolpyruvate carboxylase isoforms in Mesembryanthemum cordifolium

Tang Li

Shanghai Institute of Plant Physiology,Chinese Academy of Sciences.Shanghai 200032

Abstract

Besides the major 250 kD PEPCase isoform, a 300 kD minor PEPCase form was also found in Mesembryoanthemum cordifolium leaves. By using SDS PAGE it was found that both isoforms were homodimers. The 250 kD form consisted of two 100 kD subunits, and the 300 kD form is a dimer of two 110 kD subunits. The discrepency between molecular weights of the native enzymes and their subunits was a result of the different molecular weight determinating methods. Therefore, there is no heterodimer to PEPCase in this plant. A 1 080 kD PEPCase form was found in both salt-stressed and well-watered leaf samples. This PEPCase is an octamer, and there was no diurnal fluctuation in its abundance.

Key words: Facultative CAM plant;Mesembryanthemum cordifolium;phosphoenolpyruvate carboxylase;Quarternary structrue

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Citing This Article：

Tang Li. The study of phosphoenolpyruvate carboxylase isoforms in Mesembryanthemum cordifolium. Acta Physiol Sin 1998; 50 (2): (in Chinese with English abstract).