The protonated form of 1‐N 6‐etheno‐[erythro‐9‐(2‐hydroxy‐3‐nonyl)] adenine is identified at the active site of adenosine deaminase

FEBS Letters

Parola, Abraham H.²  Caiolfa, Valeria R.²  Gill, David¹ 

[1] Departments of Chemistry and Physics, Ben-Gurion University of the Negev, Beer-Sheva 84 105, PO Box 653, Israel

关键词: Adenosine deaminase;    1-N 6-Etheno-[erythro-9-(2-hydroxy-3-nonyl)] adenine;    Etheno-adenine;    Fluorescent inhibitor;    pH indicator;    Fluorescence polarization;    ADA;    adenosine deaminase;    ϵ-EHNA;    1-N 6-etheno-[erythro-9-(2-hydroxy-3-nonyl)] adenine;    EHNA;    erythro-9-(2-hydroxy-3-nonyl)] adenine;    2'-deoxycoformycin (Pentostatin);    [3-(2'-deoxy-β-D-erythro-pentofuranosyl)-3;    6;    7;    8-tetrahydroimidazol[4;    5-d][1;    3]diazepin-8-(R)-ol]. The abbreviation ‘ϵ’ was introduced by Secrist et al. [14] and stands for etheno;   

DOI  :  10.1016/0014-5793(90)80055-N

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A novel fluorescent competitive inhibitor of adenosine deaminase (EC 3.5.4.4) (ADA), 1-N ⁶-etheno-[erythro-9-(2-hydroxy-3-nonyl)] adenine (ϵ-EHNA), is protonated at the active site of the enzyme. In ϵ-EHNA [K ₁ = (4.06 ± 1.00) 10⁻⁶ M] part of the competive inhibition of EHNA is combined with spectroscopic properties of etheno-adenines. Computer subtraction of the fluorescence excitation spectrum of ADA from that of its equimolar complex with ϵ-EHNA yielded the corrected excitation spectrum of ϵ-EHNA at the active site of the enzyme. This spectrum mimics that of ϵ-EHNA at pH 5.5 in buffer solution and is suggested to indicate a shift in protonation equilibrium at the active site.

【 授权许可】

Unknown