Effect of L‐methionine‐DL‐sulphoximine, a specific inhibitor of glutamine synthetase, on ammonium and nitrate metabolism in the unicellular alga Cyanidium caldarium
作者:
Vittoria Martino Rigano,
Vincenza Vona,
Amodio Fuggi,
Carmelo Rigano,
期刊:
Physiologia Plantarum
(WILEY Available online 1982)
卷期:
Volume 54,
issue 1
页码: 47-51
ISSN:0031-9317
年代: 1982
DOI:10.1111/j.1399-3054.1982.tb00575.x
出版商: Blackwell Publishing Ltd
关键词: Nitrate assimilation;ammonium assimilation
数据来源: WILEY
摘要:
In the unicellular algaCyanidium caldariumnitrate utilization is strongly inhibited by ammonium and it is resumed when ammonium has been depleted. In the presence of L‐methionine‐DL‐sulphoximine (MSX), which prevents ammonium assimilation through a specific irreversible inhibition of glutamine synthetase, nitrate reduction is no longer inhibited by ammonium, and most of the ammonium derived from nitrate reduction is excreted into the external medium. However, in the presence of MSX, nitrate reduction to ammonium proceeds at a reduced rate (45 to 70% of the control); this is particularly marked at low nitrate concentration. It is hypothesized that either MSX or accumulating ammonium bring about decrease in the rate of nitrate entry into the
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