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肌红蛋白(Myoglobin,Mb)中血红素辅基不仅具有储氧功能,也能吸收特定波长的光而影响蛋白功能表达。实验发现,部分游离的氨基酸对光诱导高铁肌红蛋白(metM b,Fe(III)-Mb)的还原过程及还原程度都有重要作用,因此,本文采用紫外-可见吸收光谱、圆二色谱、三维荧光光谱法,在光照体系中加入拥挤试剂来模拟细胞内拥挤环境,研究芳香氨基酸[色氨酸(Trp)、苯丙氨酸(Phe)、酪氨酸(Tyr)、半胱氨酸(Cys)]对metM b还原的影响。结果表明,含-OH或-SH的氨基酸(Tyr、Cys)能使metM b发生较好的光还原,无-OH或-SH基团的氨基酸(Trp、Phe)对metM b的光还原作用较弱,氨基酸促进metM b光还原的整个过程可能是分子间电子转移的过程。metM b在拥挤环境聚蔗糖70(Ficoll 70)中的光诱导还原程度比在稀溶液中高,拥挤试剂Ficoll70对蛋白的二级结构起保护作用,能够稳定血红素微环境。
Hemoglobin in myoglobin (Mb) not only has the oxygen storage function, but also absorbs the light of a specific wavelength and affects the protein expression. It was found that some of the free amino acids play an important role in the light-induced reductions and reductions of metmyoglobin (metM b, Fe (III) -Mb). Therefore, UV-vis absorption spectra, circular dichroism, Three-dimensional fluorescence spectroscopy was used to simulate the intracellular crowding environment by adding crowding reagent to the illumination system. The effects of aromatic amino acids (Trp, Phe, Tyr, cysteine Cys)] on the reduction of metMb. The results showed that the amino acids with -OH or -SH (Tyr, Cys) could make metMb better photoreduction, without -OH or -SH group of amino acids (Trp, Phe) on metM b photoreduction than Weak, the entire process of amino acid to promote metM b photoreduction may be the process of electron transfer between molecules. The metMb light-induced reduction in crowded environment Ficoll 70 was higher than that in dilute solution, and the congener Ficoll70 protected the secondary structure of the protein and stabilized the heme microenvironment.