Inhibition of Na,K‐ATPase by a new ATP analog, adenosine‐5‐N′‐(2,4‐dinitro‐5‐fluorophenyl)phosphohydrazide

[摘要]

A new ATP analog, adenosine-5-N′-(2,4-dinitro-5-fluorophenyl) phosphohydrazide (DNPH-AMP), has been synthesized, which is an irreversible inhibitor of Na,K-ATPase. Interaction of the analog with the enzyme in the presence or K⁺ is describe by the scheme:, and corresponding kinetic constant k₃ and K_i are found equal to 2.5 min⁻¹ and 1.6 mM. In the presence of Na⁺ the time course enzyme inactivation by DNPH-AMP is a biphasic curve in the semilogarithmic plot, The k₃ and K_i values calculated for this case according to Fritzsch (Fritzch (1985) J. Theor. biol, 117 397) are equal to 2.45 min⁻¹ and 2.5 mM, respectively. ATP transforms the K* -type or Na,K-ATPase inactivation into the one that takes place in the presence of Na*.

[学科分类] 生物化学/生物物理

[关键词] Na;K-ATPase;ATP analog;Irreversible inhibition;DNPH-AMP;adenosine-5-N′-(2;4-dinitro-5-fluorophenyl) phosphohydrazide;MOPS;N-morpholinopropanesulfonic acid;NBS6ITP;6-[(3-carboxy-4-nitrophenyl)thiol]-9-β-D-ribifuranosylpurine triphosphate