Analytical Biochemistry 2009-03-15

Mass spectrometric quantification of neutral and sialylated N-glycans from a recombinant therapeutic glycoprotein produced in the two Chinese hamster ovary cell lines.

Kyoung-Soon Jang, Yun-Gon Kim, Geun-Cheol Gil, Sang-Ho Park, Byung-Gee Kim

Index: Anal. Biochem. 386(2) , 228-36, (2009)

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Abstract

Quality control and assurance of glycan profiles of a recombinant glycoprotein from lot to lot is a critical issue in the pharmaceutical industry. To develop an easy and simple quantitative and qualitative glycan profile method based on matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS), the modification with Girard's reagent T (GT) was exploited. Because GT-derivatized quantification of oligosaccharides using MALDI-TOF MS is possible only with neutral glycans, sialylated glycans are not subjected to quantitative analysis with MALDI-TOF MS. To solve this problem, mild methyl esterification and subsequent GT derivatization were employed, enabling us to perform rapid qualitative and quantitative analysis of sialylated and neutral N-linked oligosaccharides using MALDI-TOF MS. This modified method was used in the comparative quantification of N-glycans from the recombinant therapeutic glycoprotein expressed in two different Chinese hamster ovary (CHO) cell lines. The percentages of sialylated N-glycans to total were 22.5 and 5.2% in CHO-I and CHO-II cells, respectively, resulting in a significant difference in the biological activity of the recombinant glycoprotein.