|
|
||||||||
|
Plant Physiology 61:342-347 (1978) © 1978 American Society of Plant Biologists Regulation of Sulfate Assimilation in Plants7. Cysteine Inactivation of Adenosine 5'-Phosphosulfate Sulfotransferase in Lemna minor L. 1
Pflanzenphysiologisches Institut der Universität Bern, Altenbergrain 21, CH-3013 Bern, Switzerland, Botanisches Institut der Universität München, Menzinger Strasse 67, D-8000 München 19, Federal Republic of Germany
When 0.5 mM cysteine is added to cultures of Lemna minor L. growing with sulfate as the sole sulfur source, there is a rapid 80% loss of extractable adenosine 5'-phosphosulfate sulfotransferase. This loss is accompanied by an inhibition of sulfate uptake; however, lack of sulfate is not responsible for the decreasing adenosine 5'-phosphosulfate sulfotransferase activity. Cultivation with cysteine causes an increase in the cyst(e)ine pool of L. minor. This fact taken together with the observed inactivation of adenosine 5'-phosphosulfate sulfotransferase in crude extracts by cysteine suggests that the cysteine pool is involved in the in vivo regulation of the enzyme. The activity of adenosine 5'-phosphosulfate sulfotransferase is restored within 24 hours after transfer to a culture medium without cysteine. This restoration is partially blocked by 6-methyl purine and actinomycin D and completely by cycloheximide. Cycloheximide added to cultures of L. minor L. causes a loss of extractable APSTase comparable to the one obtained with cysteine. This loss may be in part due to cysteine, since cycloheximide causes a pronounced increase in the cysteine pool of L. minor.
1 Supported by Grant 3.610-0.75 from the Swiss National Science Foundation to C. B. and by a grant from the Deutsche Forschungsgemeinschaft to A. S. This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|