Catalytic and regulatory properties of sulphur metabolizing enzymes in cyanobacterium Synechococcus elongatus PCC 7942.
Synechococcus elongatus PCC 7942 was able to grow with several S sources. The sulphur metabolizing enzymes viz. ATP sulphurylase, cysteine synthase, thiosulphate reductase and L- and D-cysteine desulphydrases were regulated by sulphur sources, particularly by sulphur amino acids and organic sulphate esters. Sulphur starvation reduced ATP sulphurylase and cysteine synthase whereas reduced glutathione appreciated Cys degradation activity. With partially purified enzymes apparent Km values for sulphate, ATP, D- and L-Cys, thiosulphate, sulphide and O-acetyl serine were in a range of 12-50 microM. p-Nitrophenyl sulphate inhibited ATP sulphurylase competitively. Met was a feedback inhibitor of several key enzymes.
Jain
Anuradha
A
Department of Biological Sciences, Rani Durgavati University, Jabalpur, India.
Verma
Deepti
D
Bagchi
Divya
D
D002384:Catalysis; D002848:Chromatography, DEAE-Cellulose; D003542:Cystathionine gamma-Lyase / Q000037:antagonists & inhibitors / Q000378:metabolism; D003547:Cysteine Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000037:antagonists & inhibitors / Q000378:metabolism; D013430:Sulfate Adenylyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism; D013457:Sulfur Compounds / Q000378:metabolism*; D013466:Sulfurtransferases; D046940:Synechococcus / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development
D004791:Enzyme Inhibitors; D013457:Sulfur Compounds; D050862:Oxidoreductases Acting on Sulfur Group Donors; D003547:Cysteine Synthase; D013430:Sulfate Adenylyltransferase; D013466:Sulfurtransferases; C022747:thiosulfate-dithiol sulfurtransferase; D003542:Cystathionine gamma-Lyase