Goolcharran C, Cleland JL, Keck R, Jones AJS and Borchardt RT Comparison of the Rates of Deamidation, Diketopiperazine Formation and Oxidation in Recombinant Human Vascular Endothelial Growth Factor and Model Peptides AAPS PharmSci 2000; 2 (1) article 5 (https://www.pharmsci.org/scientificjournals/pharmsci/journal/5.html).

Figures and Tables

Figure 1.HPLC chromatograms showing the separation of the receptor and heparin-binding domains of rhVEGF. The receptor domain of the protein elutes with the void volume, and the heparin domain elutes at 3 minutes.

Figure 2.The RP-HPLC separation of the tryptic fragments of rhVEGF. The peaks were identified by mass analysis.

Table 1. Theoretical Tryptic Peptide Fragments of the Receptor-Binding Domain of rhVEGF

Figure 3.Kinetic profile for the degradation of the T1 tryptic fragment (open square) at pH 8.0, I = 0.5 and 37°C: open circle, deamidated product; open triangle, oxidization product; open diamond, des (AP) T1 fragment. The points represent experimental data and the lines were generated by a non-least squares curve-fitting to Equations 1-3 and the degradation pathways shown in Scheme 1.

Figure Scheme 1.

Table 2. Summary of the Rate Constants* of Degradation of rhVEGF in 100 mM Phosphate Buffer (I = 0.5) at 37°C

Table 3. Calculated Rate Constants* for the Degradation of APM at 37°C

Figure Scheme 2.

Table 4. Comparison of the Rate Constants for the Degradation of the Model Peptides and rhVEGF in 100 mM Phosphate Buffer at 37°C