Inhibition of ATP-regulated K⁺-channels by a photoactivatable ATP-analogue in mouse pancreatic β-cells

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• 作者：Ä ; mmä ; lä ; Carina ; Bokvist ; Krister ; Galt ; Sheila ; Rorsman ; Patrik
• 关键词：Potassium channel ; ATP-regulated ; caged ATP ; β ; -Cell ; ATP-regulated potassium channel ; DMNPE-caged ATP ; dimethyl-nitrophenyl-ethyl-ester ATP ; K_ATP-channel ; ATP-regulated K⁺-channel ; UV ; ultraviolet
• 刊名：Biochimica et Biophysica Acta (BBA)/Molecular Cell Research
• 出版年：1997
• 出版时间：May 17, 1997
• 年：1997
• 卷：1092
• 期：3
• 页码：347-349
• 全文大小：290 K

文摘

The effects of a photoactivatable (DMNPE-caged) ATP-analogue on ATP-regulated K⁺-channels (K_ATP-channel) in mouse pancreatic β-cells were investigated using the inside-out patch configuration of the patch-clamp technique. The caged precursor caused a concentration-dependent reduction of channel activity with a K_i of 17 μM; similar to the 11 μM obtained for standard Mg-ATP. The small difference in the blocking capacity between the precursor and ATP is probably the reason why no change in channel activity was observed upon photolysis of the caged molecule and liberation of ATP. It is suggested that the part of the ATP molecule involved in the blocking reaction of the K_ATP-channel is not sufficiently protected in DMNPE-caged ATP making this compound unsuitable for studying the rapid kinetics of ATP-induced K_ATP-channel inhibition.