Effects of PEGylation on the Lowry method for the content determination of trichosanthin

The current study was designed to establish a method for examining whether the content of PEG-TCS could be determined by the Lowry method. The research applicability of the Lowry method on the determination of PEGylated trichosanthin (PEG-TCS) protein content was proposed for the first time. Procedures were designed to determine whether residual PEG interfered with the result of protein content determination, PEG (≤20 µg/ml) interference was not apparent. The interference of a PEGmodified group was analyzed by utlra violet spectrophotometric colorimetry, and the differences in the rates were 5.0 and 6.2%. The linearity, precision, and recovery were determined. There is good linear relationship from 30 to 70 μg/ml PEG-TCS. The experiment results provided sufficient data to establish a quality control method for the determination of PEG-TCS content, and they were conducive to the determination method establishment of other PEGylated proteins for non clinical experiment application.