Fig. 1. MALDI linear TOF mass spectra of apoCIII in VLDL.

Proteins in the VLDL fraction from a healthy individual were analyzed by MALDI linear TOF MS. The mass region of m/z 8,700–10,000 covering all apoCIII glycoforms is presented. The average mass of the protonated molecular ions of each isoform is indicated in parentheses. The glycoform is given at the corresponding peak. square, GlaNAc; circle, Gal; diamond, NeuAc; short wavy line, unglycosylated apoC3. (a) before enzymatic treatment. (b) after desialylation. (c) after deglycosylation. (d) equimolar mixture of desialylated and deglycosylated samples.