猪心肌高铁肌红蛋白还原酶高级结构及功能域的荧光表征

Identification on Molecular Structure and Domains of pMetMbase A by Fluorescence Spectra

猪高铁肌红蛋白还原酶(pMetMbase A)是肌红蛋白氧化还原系统中被新认识的还原酶,它的分子结构有待荧光光谱表征。本研究采用普通及同步荧光法,以求证该酶特征荧光发射光谱和结构功能域。pMetMbase A的优化荧光光谱条件是,扫描速度600nm/min、光栅狭缝10nm、溶液浓度1.0×10-2mmol/L、激发光波长270nm和波长差20nm。结果表明,pMetMbase A具有自己的特征荧光发光谱带;311和349.5nm处分别是酪氨酸和色氨酸残基的特征荧光;650nm处是其卟啉环-铁(heme-Fe)双硫键的特征荧光,推测为电子传递和还原反应的核心活性位点。因此,该pMetMbase A具备蛋白质的肽链和heme-Fe结构。

pMetMbase A found and purified by our lab was a new reductase in the myoglobin reducing system.Its molecular structure and domains should be identified by fluorescence spectra.The optimal fluorescence conditions of pMetMbase A were designed as 600nm/min scanning speed,10nm slit width,1.0 × 10-2mmol/L,270nm excitation wavelength and 20nm Δλ.The results showed pMetMbase A had its own specific fluorescence emission band.The fluorescence peaks of tyrosine and tryptophan residue were located at 311nm and 349.5nm,respectively.While,there was fluorescence peak of porphyrin ring-iron（heme-Fe） at 650nm which may origins from the core active site for electronic transmission and redox reaction.Therefore,pMetMbase A has peptide chain of protein structure with special domain heme-Fe ring as a new globin reductase.