[Laser Raman and infrared spectrum analysis of low-density lipoproteins purified from hen egg yolk].

During the experiment, diversified proteins were separated from hen egg yolk by ammonium sulphate rapid fractionation, and pure LDL was obtained after filtrating through Sephadex G-200 chromatography. After the qualitative detection of SDS-PAGE, the authors discovered that LDL consists of five major apoprotein. The Raman and infrared spectrum showed CH2 asymmetric stretching and symmetric stretching mode. However, the authors found C==O stretching vibrations of protein peptide bonds and N+ (CH3)3 asymmetric stretching vibration from the choline group in phospholipids. Laser Raman and infrared spectrum analysis of LDL provided useful information for studying their structure.