Localization of enzymes of assimilatory sulfate reduction in pea roots

Brunold, Christian; Suter, Marianne (1989). Localization of enzymes of assimilatory sulfate reduction in pea roots. Planta, 179(2), pp. 228-234. Springer 10.1007/BF00393693

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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 35SO 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 35SO 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.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS) > Stress Physiology (discontinued)
08 Faculty of Science > Department of Biology > Institute of Plant Sciences (IPS)

UniBE Contributor:

Brunold, Christian and Suter, Marianne

Subjects:

500 Science > 580 Plants (Botany)

ISSN:

0032-0935

Publisher:

Springer

Language:

English

Submitter:

Peter Alfred von Ballmoos-Haas

Date Deposited:

13 Jun 2018 17:56

Last Modified:

24 Oct 2019 06:48

Publisher DOI:

10.1007/BF00393693

Uncontrolled Keywords:

ATP-sulfurylase; Adenosine 5′-phosphosulfate sulfotransferase; Pisum; Sulfate reduction; Proplastid; Sulfite reductase

BORIS DOI:

10.7892/boris.107345

URI:

https://boris.unibe.ch/id/eprint/107345

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