【摘要】 为了进一步了解胰岛素构象与功能的关系,测定了不同条件下胰岛素和它的类似物的内源萤光光谱,胰岛素类似物包括去B链羧端五肽胰岛素,去B链羧端七肽胰岛素和去B链羧端八肽胰岛素。它们的发射光谱的峰在306nm,激发光谱峰在277nm。不同pH值,不同浓度的十二烷基硫酸钠和温度变化对胰岛素的荧光光谱的影响和对类似物的影响非常相似。说明这些类似物的环境酪氨酸残基的微环境是相似的。由于去五肽胰岛素有接近于天然胰岛素的生物活力,去七肽胰岛素没有生物活力,因此说明,胰岛素分子的受体结合部位中,B_24～25两个苯丙氨酸侧链本身具有重要的地位。并不是因为失去它们后引起胰岛素构象变化而失活的。更多还原

【Abstract】 The intrinsic fluorescence spectra of Ins and its analogs DPI, DHPI and DOIhave been studied. The peak of the emission spectra of Ins is at 306nm and that of theexcited spectra is at 277 nm. DPI DHPI and DOI all give similar emissive spectra as that of Ins, but theirintensities differ slightly from each other. The effects of pH, SDS and temperature on the fluorescence intensity of Ins arevery much similar to those of DPI, DHPI and DOI. It is suggested that the nature of the microenvironment around the tyrosine sidechains of Ins, DPI, DHPI and DOI are of the same kind. It was reported previously that DPI has essentially full activity of Ins, whileDHPI and DOI are inactive. There may be alternative mechanisms for the inactivityof DHPI and DOI. One is the conformational change, caused by loss of B₂₄ and B₂₅Phe from the C-terminal of the B-chain of Ins, the other is the role that the two Pheresidues themselves play in the receptor-binding site of Ins. The results described in this paper along with the CD measurements, givepreference to the latter mechanism.更多还原