Interaction of thioredoxin with oxidized aminobutyrate aminotransferase Evidence for the formation of a covalent intermediate

FEBS Letters

Churchich, Jorge E.¹  Park, Joohong¹ 

[1] Department of Biochemistry, University of Tennessee, Knoxville, TN 37996-0840, USA

关键词: Aminotransferase;    Disulfide exchange;    Thioredoxin;    Fluorescence;    Covalent intermediate;    Protein interaction;    PQQ;    pyrroloquinoline quinone;    DTNB;    5;    5′-dithio bis-(2-nitrobenzoic acid);   

DOI  :  10.1016/0014-5793(92)81132-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Pig brain 4-aminobutyrate aminotransferase is inactivated by pre-incubation with pyrroloquinoline quinone (2,7,9-tricarboxy-1H-pyrrolo[2,3,f]quinoline-4,5-dione; PQQ) at pH 7. The reaction of approximately 2 SH residues/dimer is sufficient to inactivate the enzyme. Reoxidized aminotransferase is reactivated by E. coli thioredoxin. Similar results were obtained with E. coli 4-aminobutyrate aminotransferase. The spectroscopic properties of thioredoxin, tagged with the fluorescence probe, anthraniloyl, were used to monitor its interaction with re-oxidized 4-aminobutyrate aminotransferase. During the regeneration of native aminotransferase by thioredoxin, the substrate forms a covalent intermediate with the oxireductase, as revealed by gel filtration chromatography. It is postulated that the substrate (oxidized aminotransferase) forms a covalent intermediate with thioredoxin through disulfide linkages.

【 授权许可】

Unknown