Akademik Veri Yönetim Sistemi
International Proteomics Congress // 6th National Proteomics Congress, Kocaeli, Türkiye, 10 - 11 Ocak 2024, (Özet Bildiri)
Aim: Glycosylation is a post-translational modification where glycan groups are added to proteins, impacting their structural and functional properties. Managed by around 200 glycosyltransferase enzymes and influenced by environmental factors, this process is vital for Immunoglobulin G (IgG) glycoproteins, which are key antibodies in immune responses. Glycosylation motifs in the Fc region of IgGs are essential for targeting immune cells.
Ethyl esterification is a derivatization technique that improves the ionization of sialic acid groups, enhancing the accuracy of MALDI-TOF mass spectrometry. This method is less chemically reactive than others, preserving glycan integrity and specifically targeting 2,3- and 2,6-sialic acids for reliable analyses.
This study investigates the stability of ethyl esterified glycans at different storage temperatures (+4°C, -20°C, and -80°C) to determine how long they can be reliably stored after derivatization.
Methods: For this study, Immunoglobulin G (IgG) was isolated from serum samples. Following isolation, the glycans attached to IgGs were cleaved using PNGase F. The released glycans were then derivatized through ethyl esterification with EDC and HOBT. Subsequently, the derivatized glycans were purified using handmade cotton columns and stored at three different temperatures (+4°C, -20°C, and -80°C). The samples were analyzed at various time points using a Bruker Rapiflex MALDI-TOF mass spectrometer.
Results: Ethyl esterified glycans show changes after day 0 when stored at +4, -20 and -80 degrees. Bisectic glycans decreased, while fucoses increased and decreased. Galactosylated glycans also increased, while sialylated glycans increased and decreased.
Conclusion: Despite the limited sample size, it was observed that glycans, following ethyl esterification, did not maintain stability across different storage temperatures. Therefore, it is recommended that analyses be conducted immediately after the ethyl esterification reaction to achieve more reliable experimental results.