摘要
用高效蛋白层析柱纯化破伤风毒素的 B 片段,用膜片箝(patch clamp)技术证明纯化的 B 片段于人工磷脂膜上能够形成离子通道.在中性和酸性 pH 时形成离子通道的几率很小,在有 pH 梯度存在的情况下却较容易测到通道活性.形成的离子通道的电导系数为2.3pS.B 片段形成的离子通道允许 K^+双向通过.离子通道打开的持续时间一般在20—120ms之间,多为20—40ms 和 100—120ms;闭合持续时间一般在20—40ms 间,多为20ms.表明通道的开和闭非常频繁.
The ion channel formation of fragment B of tetanus toxin in an artificial lipid bilay-er was described.Fragment B with a molecular weight of 48000 was purified by fastprotein liquid chromatography.The channel activities were recorded from an asolectinbilayer memberane by patch clamp technique.It rarely formed ion channels at neutral oracidic pHs.In contrast,with pH gradient the channel activities of fragment B were easilyrecorded.By analysis of single channels formed by fragment B,the conductance of thechannel was 2.3pS.At different holding potentials(—100—+150mV)the channels gavesame conductance,it indicated that“the fragment B channel”passed K ion in both direc-tions.The opening-time of the channel was maintained at 20—40 and 100—120ms,and theclosing-time of it was main at 20ms.These results indicated that the channel of fragmentB was rapidly flickering between the states of opening and closing.
出处
《生物化学与生物物理进展》
SCIE
CAS
CSCD
北大核心
1993年第2期115-119,共5页
Progress In Biochemistry and Biophysics
