Using density gradient techniques we have shown that in addition to a location within the cytoplasm all the enzymes of the pentose phosphate pathway are also present within the plastids of apical cells of pea roots. The data are discussed in relation to the hypothesis that the pentose phosphate path
The intracellular location of the enzymes of nitrate assimilation in the apices of seedling pea roots
β Scribed by M. J. Emes; M. W. Fowler
- Publisher
- Springer-Verlag
- Year
- 1979
- Tongue
- English
- Weight
- 498 KB
- Volume
- 144
- Category
- Article
- ISSN
- 0032-0935
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β¦ Synopsis
The intracellular distribution of the enzymes of nitrate and ammonia assimilation in apical cells of pea (Pisum sativum L.) roots is described. Nitrate reductase (EC 1.6.6.2) was found to have no organelle association, and is considered to be located in the cytosol or possibly loosely bound to the outside of an organelle. Nitrite reductase and glutamate synthase (EC 2.6.1.53) are plastid located, as is glutamine synthetase (EC 6.3.1.2) although this enzyme also has activity in the cytosol. Glutamate dehydrogenase (EC 1.4.1.3) was found only in the mitochondrion.
π SIMILAR VOLUMES
Plastids were separated from extracts of pea (Pisum sativum L.) roots by sucrose-densitygradient centrifugation. The incubation of roots of intact pea seedlings in solutions containing 10 mM KNO3 resulted in increased plastid activity of nitrite reductase and to a lesser extent glutamine synthetase.