| Autor: |
Soares, M.I.M., Cresswell, C.F. |
| Zdroj: |
South African Journal of Botany; June 1984, Vol. 3 Issue: 3 p146-152, 7p |
| Abstrakt: |
The activity and distribution of barley (Hordeum vulgareL.) leaf nitrate reductase in sucrose density gradients varied with the composition of the extraction medium. Removal of Dithiothreitol — Cleland’s Reagent (DTT) resulted in an increase of nitrate reductase activity throughout the gradient (especially at the low density fractions) but decreased the percentage of the total activity associated with the organelles. Nitrate reductase activity was scattered in floating gradients and in non-floating gradients which were subjected to either long or short centrifugation. This pattern was not affected by the addition of bovine serum albumin (BSA). In crude extracts DTT preserved the activity of nitrate reductase. Possible explanations for the observed effect of DTT on the activity and distribution of nitrate reductase in sucrose density gradients are discussed and include: a) dissociation of a nitrate reductase complex system, b) release of nitrate reductase from a membranous system and c) interference with the nitrite accumulating properties of the enzyme in the in vitroassay system. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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