Skip to main content
. 2024 Nov 22;27(12):111457. doi: 10.1016/j.isci.2024.111457

Figure 1.

Figure 1

The effect of passport sequence on the galactosylation and sialylation levels of recombinant EPO

(A) Tagging with the passport sequence increased the sialylation level of recombinant EPO produced in Expi293F cells. The sialylation level was determined through immunoblotting using an anti-FLAG antibody and lectin blotting using MAM.

(B) The N-glycans of recombinant EPO, with or without the passport sequence, were analyzed by MALDI-TOF-MS. The predicted structures, based on their mass values and the biosynthetic pathway, are shown above the profiles. The identities of sugar residues were inferred from the literature and are represented by symbols according to the Symbol Nomenclature for Glycans (SNFG) system. Details can be found at NCBI (http://www.ncbi.nlm.nih.gov/books/NBK310273/): GlcNAc, blue square; Man, green circle; Gal, yellow circle; Neu5Ac, magenta diamond; Fuc, red triangle.

(C) The galactosylation and sialylation levels of EPO, with or without the passport sequence, were calculated based on the peak intensities of MALDI-TOF-MS profiles. Error bars represent the standard error of the mean (SEM) from three independent transfections. Statistical significance was assessed by an unpaired t test: ∗∗∗∗p < 0.0001 and ∗∗p < 0.001.