Fig 5. Comparison of mouse and human apoD molecular weight and impact of N-glycan and sialic acid removal.

Mouse and human brain and plasma samples were separated by PAGE under conditions that yielded approximately equal apoD loading. Both brain and plasma samples were pre-incubated with either PNGase (“+”) or NMDase (“+”), or the appropriate buffer controls (“-“), to assess the impact of N-glycans and sialic acids, respectively, on overall MW. The broken lines clarify the migration distances of the different samples and indicates that the differences in MW (comparing brain and plasma samples) are not due to sialylation alone (as the MW of plasma apoD is still greater than that of brain apoD after sialic acid removal). In addition, the difference between brain and plasma apoD MW identified in the mouse samples are recapitulated in the human brain and plasma samples. PNGase, peptide N-glycosidase F; NMDase, neuraminidase.