Encinas M V, Olsen L R, Díaz J F, Andreu J M, Goldie H, Cardemil E
Departamento de Ciencias Químicas, Facultad de Química y Biología, Universidad de Santiago de Chile.
Biochim Biophys Acta. 1995 Sep 27;1252(1):23-7. doi: 10.1016/0167-4838(95)00107-6.
The secondary structure of Saccharomyces cerevisiae and Escherichia coli phospho enolpyruvate (PEP) carboxykinases was quantitatively examined using circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopies. From CD analyses, values of 24% alpha-helix and 38% beta-sheet were obtained for the E. coli enzyme, while the corresponding values for the S. cerevisiae PEP carboxykinase were 20% and 36%. Analysis of the amide I' infrared band indicated 20% alpha-helix and 36% beta-sheet for the S. cerevisiae enzyme, while for the E. coli protein values of 40% beta-sheet and between 9 and 36% alpha-helix could be inferred. It is concluded that the bacterial enzyme has more secondary structure elements than the yeast protein. No alteration of the CD or FTIR spectra was detected upon substrate or metal ion binding to any enzyme.
利用圆二色性（CD）和傅里叶变换红外（FTIR）光谱法对酿酒酵母和大肠杆菌磷酸烯醇丙酮酸（PEP）羧激酶的二级结构进行了定量检测。通过CD分析，大肠杆菌酶的α-螺旋值为24%，β-折叠值为38%，而酿酒酵母PEP羧激酶的相应值分别为20%和36%。对酰胺I'红外波段的分析表明，酿酒酵母酶的α-螺旋为20%，β-折叠为36%，而对于大肠杆菌蛋白，可以推断β-折叠值为40%，α-螺旋值在9%至36%之间。得出的结论是，细菌酶比酵母蛋白具有更多的二级结构元件。在底物或金属离子与任何一种酶结合时，未检测到CD或FTIR光谱的变化。
