期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1970
卷号：65
期号：3
页码：729-736
DOI：10.1073/pnas.65.3.729
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Nitrate reductase activity in barley (Hordeum vulgare L. cv. Himalaya) aleurone layers has been determined in the intact tissue, using two different methods. The first method measures the rate of appearance of H218O produced during the reduction of KN18O3. The second assay measures excreted nitrite resulting from nitrate reduction under anaerobic conditions. Nitrite production in this anaerobic, intact-tissue assay was dependent upon the presence of phosphate (pH 7.5) and was increased by ethanol and bisulfite. After ten hours of nitrate induction, nitrate reductase activities measured by the KN18O3 assay are one-sixth, and those measured by the anaerobic intact-tissue assay are one-third, of those observed in cell-free extracts of aleurone layers. Addition of ethanol to the anaerobic intact-tissue medium increased the rate of nitrate reduction to a level greater than that found in the cell-free assay. Oxygen inhibited nitrite release in the anaerobic intact-tissue assay. However, under aerobic conditions and in the presence of 2-heptyl-4-hydroxyquinoline-N-oxide or antimycin A, nitrate reduction increased to rates comparable to those observed under anaerobiosis. Neither of these electron transport inhibitors affected anaerobic nitrate reduction, though they were effective in inhibiting oxygen uptake in separate experiments.
