Presence of ε‐adenosine tetraphosphate in chromaffin granules after transport of ε‐ATP

FEBS Letters

Gualix, Javier¹  Abal, Miguel¹  Pintor, Jesús¹  Miras-Portugal, Maria Teresa¹ 

[1] Departamento de Bioquímica, Facultad de Veterinaria, Universidad Complutense, E-28040 Madrid, Spain

关键词: Adenosine 5′-tetraphosphate;    Vesicular transport;    Etheno-adenine nucleotide;    Transphosphorylation;    Chromaffin granule;    Ap4;    adenosine 5′;    tetraphosphate;    ϵ-Ap4;    1;    N-6-ethenoadenosine 5′-tetraphosphate (etheno-Ap4);    ϵ-ATP;    1;    N-6-ethenoadenosine 5′;    tetriphosphate (etheno-ATP);    HPLC;    high-performance liquid chromatography;   

DOI  :  10.1016/0014-5793(96)00732-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Adenosine 5′-tetraphosphate (Ap₄) is a natural constituent of chromaffin granules with concentration values of 2.2±0.1 nmol/mg of protein and a ratio 245±40 times lower with respect to ATP (n=4). The granular transport of ε-ATP resulted in a time- and concentration-dependent production of ε-adenosine tetraphosphate (ε-Ap₄) at the intragranular level. The ε-Ap₄ formation followed a hyperbolic saturation kinetic at low ε-ATP concentrations with K _m value of 0.4 μM ε-ATP intragranular (1.15 pmol/mg of granular protein). Intragranular concentrations of ε-ATP higher than 500 pmol/mg of protein (≈ 175 μM intragranular) resulted in a non-saturable production of ε-Ap₄.

【 授权许可】

Unknown