Table 2. Quantitative distribution of MBP83–99 breakdown products
Peak Peptide sequence Protease Control cells, % Autophagic cells, %
1 IVTPRTP AEP 21.5 12.6
2 NIVTPRTP Cat S/L 3.3 2.2
3 FKNIVTPRTP Cat D 2.2 3.2
4 ENPVVHF Cat D 7.0 5.0
5 NPVVHFFKN 2.5 0.5
6 FFKNIVTPRTP Cat S/L 1.4 1.2
7 ENPVVHFFKN AEP 17.2 12.9
8 ENPVVHFFK Cat S/L 3.6 1.5
9 VVHFFKNIVTPRTP 1.3 1.2
PVVHFFKNIVTPRT
10 NPVVHFFKNIVTPRTP 3.2 1.1
11 ENPVVHFFKNIVTPRTP Undigested 36.6 58.7
  • Breakdown products were quantified by their peak heights in the RP-HPLC chromatogram. The total amount of identified peptides was set to 100%. Shown are the differences between control cells and cells undergoing 24 h of autophagy and the lysosomal proteases, which are known to be responsible for the generation of the corresponding fragments (18).