A new role for thioredoxin in assimilatory sulphate reduction

FEBS Letters

Schwenn, J.D.¹  Schriek, U.¹ 

[1] Biochemistry of Plants, Ruhr University Bochum, PO Box 102148, 4630 Bochum 1, FRG

关键词: Enzyme activation;    ATP:adenylylsulfate 3′-phosphotransferase;    Thioredoxin;    Assimilatory sulfate reduction;    Chlamydomonas reinhardii;    APS-kinase;    ATP:adenylylsulphate 3′-phosphotransferase (EC 2.7.1.25);    APS;    adenylyl 5′-phosphosulphate;    DTE;    dithioerythritol;    DTT;    dithiothreitol;    GSH;    reduced glutathione;    PAPS;    3′-phosphoadenylyl 5′-phosphosulphate;    Thio;    thioredoxin;   

DOI  :  10.1016/0014-5793(84)81372-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The activity of isolated APS-kinase (EC 2.7.1.25) from the green alga Chlamydomonas reinhardii CW15 was stimulated by catalytic amounts of spinach thioredoxin f. The stimulation amounted to a factor of 3 in the presence of excess reducing thiols. A regulatory function of thioredoxin f was deduced from two observations: (a) the enzyme supported a low basal rate of PAPS formation in the absence of its effector, and (b) the saturation of the enzyme activity by thioredoxin f was sigmoidal. No evidence has been obtained of thioredoxin f serving as in the reduction of PAPS to sulphite in this alga. The slight increase in sulphite formation as observed with enriched spinach thioredoxin m is assumed to be due to a residual APS-kinase contaminating the partially purified sulpho-nucleotide unspecific sulphotransferase.

【 授权许可】

Unknown