Table 2.

Tandem mass spectometric identification of apolipoproteins J, E2, E4, L and A-IVa

ProteinPeptide noExperimental [M + H]Predicted [M + H1]SequencePosition in Protein
The tryptic fragments here reported were obtained by the fragmentation of two proteins purified by two-dimensional electrophoresis that correspond to spots 1, 3, 4, 5, and 6 of Figure 1.
aFive tryptic peptides analyzed from spot 1 correspond to apo J with a 16% homology. Eight tryptic peptides analyzed from the 28-kD protein (spot 6) correspond to the sequence of human apo A-IV ((18)). Considering the lower molecolar mass and the homology of the tryptic composition (59%), the protein was considered a fragment of apo A-IV. Four tryptic peptides analyzed from the 42-kD digest correspond to apo L precursor ((19)). These peptides covered 17% of apo L precursor. For spot 4 and spot 5, five and four peptides correspond to E2 and E4 with a 41% homology.
Apo J (spot 1)11074.601074.60RPHFFFPK215-222
21392.661392.68ASSIIDELFQDR183-194
31793.811799.80FMETVAEKALQEYR430-443
41871.881781.84QQTHMLDVMQDHFSR168-182
52313.252313.17VTTVASHTSDSDVPSGVTEVVVK386-408
Apo L (spot 3)11274.601274.64VNEPSILEMSR306-316
21595.721595.83WWTQAQAHDLVIK219-231
31630.801630.79VTEPISAESGEQVER291-305
42487.102487.25EFLGENISNFLSLAGNTYQLTR241-262
Apo E2 (spot 4)1898.47898.43FWDYLR33-38
21646.781646.79GEVQMLGQSTEELR120-134
31729.831729.84SELEEQLTPVAEETR76-90
41752.901752.89KVEQAVETEPEPELR1-15
52729.382729.39WVQTLSEQVQEELLSSQVTQELR39-61
Apo E4 (spot 5)1898.47898.43FWDYLR11-16
21646.781646.79GEVQAMLGQSTEELR98-112
31729.831729.84SELEEQLTPVAEETR54-68
42729.382729.39WVQTLSEQVQEELLSSQVTQELR17-39
Apo A-IV (spot 6)1975.55975.51ISASAEELR122-130
21083.561083.54LTPYADEFK67-75
31104.591104.57LEPYADQLR1-9
41258.681258.68IDQTVEELRR78-87
51258.681258.68GNLKGNTEGLQK142-153
61287.621287.67TQVNTQAEQLR10-20
71558.761558.80LNHQLEGLTFQMK100-112
81933.971933.99ENADSLQASLRPHADELK36-53