Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.4 (nitrite reductase)
 1,847 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cadmium (Cd(2+)) or copper (Cu(2+)) ions are toxic for Chlamydomonas reinhardtii growth, at 300 microM, and the alga may accumulate about 0.90+/-0.02 and 0.64+/-0.02% of its dry weight, respectively. Metal contamination changes the elemental composition of dried alga biomass, which indicates the possibility to use C. reinhardtii as biosensor and bioremediator of the aquatic contamination by heavy metals. Either, Cd(2+) or Cu(2+), inhibits about 20% of the nitrate consumption rate by the cells, while only Cd(2+) increases about 40% the sulfate consumption rate. The presence of 1 mM calcium (Ca(2+)) in the culture medium increases the C. reinhardtii productivity (about 50%), the nitrate uptake rate (about 20%) and the sulfate uptake rate (about 30%). In addition, Ca(2+) overcomes the Cd(2+) (300 microM) toxicity by decreasing (about 35%) the intracellular accumulation of metal. Sulfur-starvation induces in C. reinhardtii the expression of serine acetyltransferase and O-acetylserine(thiol)lyase activities, but decreases 50% the consumption rate of nitrate by the cells. Sulfate is also required for the full expression of the nitrate reductase (NR), nitrite reductase (NiR) and glutamate synthase activities.
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PMID:Metal toxicity in Chlamydomonas reinhardtii. Effect on sulfate and nitrate assimilation. 1291 98

The localization of enzymes of assimilatory sulfate reduction was examined in roots of 5-d-old pea (Pisum sativum L.) seedlings. During an 8-h period, roots of intact plants incorporated more label from (35)SO 4 (2-) in the nutrient solution into the amino-acid and protein fractions than shoots. Excised roots and roots of intact plants assimilated comparable amounts of radioactivity from (35)SO 4 (2-) into the amino-acid and protein fractions during a 1-h period, demonstrating that roots of pea seedlings at this stage of development were not completely dependent on the shoots for reduced sulfur compounds. Indeed, these roots contained activities of ATP-sulfurylase (EC 2.7.7.4), adenosine 5'-phosphosulfate sulfotransferase, sulfite reductase (EC 1.8.7.1) and O-acetyl-L-serine sulfhydrylase (EC 4.2.99.8) at levels of 50, 30, 120 and 100%, respectively, of that in shoots. Most of the extractable activity of adenosine 5'-phosphosulfate sulfotransferase was detected in the first centimeter of the root tip. Using sucrose density gradients for organelle separation from this part of the root showed that almost 40% of the activity of ATP-sulfurylase, adenosine 5'-phosphosulfate sulfotransferase and sulfite reductase banded with the marker enzyme for proplastids, whereas only approximately 7% of O-acetyl-L-serine sulfhydrylase activity was detected in these fractions. Because their distributions on the gradients were very similar to that of nitrite reductase, a proplastid enzyme, it is concluded that ATP-sulfurylase, adenosine 5'-phosphosulfate sulfotransferase and sulfite reductase are also exclusively or almost exclusively localized in the proplastids of pea roots. O-Acetyl-L-serine sulfhydrylase is predominantly present in the cytoplasm.
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PMID:Localization of enzymes of assimilatory sulfate reduction in pea roots. 2420 22