Isolation and characterization of sulfhydryl and disulfide peptides of human apolipoprotein B-100.
Twenty-three of the 25 cysteine residues in apolipoprotein B-100 have been isolated directly from tryptic or peptic peptide mixtures. Sixteen cysteine residues exist in disulfide forms: Cys-1-Cys-3, Cys-2-Cys-4, Cys-5-Cys-6, Cys-7-Cys-8, Cys-9-Cys-10, Cys-11-Cys-12, Cys-13-Cys-14, and Cys-20-Cys-21. All of these except Cys-20-Cys-21 are recently discovered disulfide linkages. In addition to Cys-22 and Cys-24, which have been described as sulfhydryls on low density lipoprotein, Cys-15 to Cys-18 and Cys-23 are in the reduced form. Cys-19 and Cys-25 are not yet confirmed. Our results revealed that all identified disulfide linkages are located in the trypsin-releasable regions and that all except Cys-1-Cys-3 and Cys-2-Cys-4 are linked to the neighboring cysteine. We propose a linear model of apolipoprotein B-100 in low density lipoprotein that wraps around the low density lipoprotein molecule.
Yang
C Y
CY
Baylor College of Medicine, Houston, TX.
Kim
T W
TW
Weng
S A
SA
Lee
B R
BR
Yang
M L
ML
Gotto
A M
AM
D000595:Amino Acid Sequence; D053299:Apolipoprotein B-100; D001055:Apolipoproteins B / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000032:analysis; D008077:Lipoproteins, LDL / Q000097:blood / Q000302:isolation & purification; D008961:Models, Structural; D008969:Molecular Sequence Data; D010434:Pepsin A; D010446:Peptide Fragments / Q000302:isolation & purification; D011487:Protein Conformation; D013438:Sulfhydryl Compounds / Q000032:analysis; D014357:Trypsin
D053299:Apolipoprotein B-100; D001055:Apolipoproteins B; D004220:Disulfides; D008077:Lipoproteins, LDL; D010446:Peptide Fragments; D013438:Sulfhydryl Compounds; D014357:Trypsin; D010434:Pepsin A