Conformational responses of an arachidonate‐ and U46619‐binding haemoprotein in relation to platelet activation

FEBS Letters

Jamaluddin, Moideen P.¹  Krishnan, Lissy K.¹ 

[1] Thrombosis Research Unit, Sree Chitra Tirunal Institute for Medical Sciences & Technology, Trivandrum 695 012, India

关键词: Platelet activation;    Hemoprotein;    Antibody;    Conformational change;    ADP;    Ionophore A23187;    Cold activation;   

DOI  :  10.1016/0014-5793(87)81347-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Antibodies were raised, in rabbits, against an arachidonate- and U46619-binding protein purified from calf platelets. Spectral measurements and immunodiffusion experiments were employed to follow conformational responses of the protein in relation to platelet activation. Upon treatment with the platelet agonists, arachidonate and PGH₂, as well as the common haem ligands, imidazole and CN⁻, the purified protein had its Soret band red-shifted, with hypochromicity, but the protein saturated with the agonists, not with the haem ligands, showed altered antigenic properties in immunodiffusion experiments. In an analogous manner activation of gel-filtered calf platelets with high concentrations of ADP and A23187, as well as by cold, had Soret bands of extracts of sonicated platelets red-shifted, with hypochromicity; concomitantly, antigenically different conformations of the protein appeared in Triton X-100 extracts of the activated platelets. A protein immunologically related to the platelet protein was detected in Triton X-100 extracts of calf neutrophils. It is suggested that conformational changes of the protein induced by arachidonate or prostaglandin endoperoxides or H₂O₂ formed in different compartments during platelet activation by different stimuli may be a biochemical mechanism of stimulus-response coupling and that similar mechanisms might operate in other cell types.

【 授权许可】

Unknown