Site‐directed mutagenesis of K396R of the 65 kDa glutamic acid decarboxylase active site obliterates enzyme activity but not antibody binding

FEBS Letters

Lernmark, Åke²  Hampe, Christiane S.²  Robertson, John¹  Falorni, Alberto³  Hammerle, Lisa P.² 

[1] Diamyd Medical AB, Karolinska Hospital, Stockholm, Sweden;Department of Medicine, Box 357710, University of Washington, Seattle, WA 98195, USA;Department of Internal Medicine, Section of Internal Medicine and Endocrine and Metabolic Sciences, University of Perugia, Perugia, Italy

关键词: Glutamate decarboxylase;    Autoimmunity;    Pyridoxal 5-phosphate;    Diabetes;    GAD65;    65 kDa glutamate decarboxylase;    PLP;    pyridoxal 5-phosphate;    rhGAD65;    recombinant human GAD65;    GAD65Ab;    antibodies to GAD65;    RIA;    radioimmunoassay;    ICA;    islet cell antibodies;   

DOI  :  10.1016/S0014-5793(00)02429-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The role of K396 in the enzymatic catalysis and the antigenicity of the 65 kDa isoform of glutamate decarboxylase (GAD65) was analyzed using the K396R GAD65 mutant. GAD65 is a major autoantigen in Type 1 diabetes and autoantibodies directed to GAD65 are widely used markers for this disease. We found that (1) recombinant human GAD65 is fully enzymatically active; (2) the K396R mutation abolished GAD65 activity; and (3) the K396R mutant retained full antigenicity to GAD65 autoantibodies in serum from Type 1 diabetes patients, but not to polyclonal antibodies raised to the catalytic domain.

【 授权许可】

Unknown