Premium
Role of phosphoenolpyruvate carboxylase in malate production by the developing barley aleurone layer
Author(s) -
Macnicol Peter K.,
Raymond Philippe
Publication year - 1998
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1998.1030116.x
Subject(s) - aleurone , phosphoenolpyruvate carboxylase , hordeum vulgare , pyruvate kinase , phosphoenolpyruvate carboxykinase , biochemistry , pyruvate carboxylase , glyoxylate cycle , malic enzyme , biology , malic acid , glycolysis , chemistry , botany , enzyme , poaceae , citric acid , dehydrogenase
The pathway of malate synthesis in the developing aleurone layer of barley ( Hordeum vulgare L. cv. Himalaya) was investigated. Malate formation did not occur under anoxia. Labelling with [2‐ 14 C]acetate showed that the glyoxylate pathway was not a significant source of malate. The partitioning of glycolytic carbon flux at the branchpoint between phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) and pyruvate kinase (PK, EC 2.7.1.40) was studied using [U‐ 14 C]glucose. It was concluded that in aleurone from maturing, rapidly acidifying grains the flux through the PEPC branch relative to that through PK is 3‐5 times greater than in young aleurone. This increase in flux can be accounted for by a 5‐fold increase in PEPC protein determined by western blotting and in PEPC activity measured in vitro.