Rapid purification and characterization of human platelet glycoprotein V: the amino acid sequence contains leucine-rich repetitive modules as in glycoprotein Ib.
Glycoprotein V (GPV) is a membrane-associated, 82 Kd platelet glycoprotein that is hydrolyzed during thrombin activation to yield 69 Kd fragment. We have developed a rapid and simple method for isolation of the protein from platelet extracts using a combination of gel permeation, anion-exchange, and lectin affinity chromatography. The partial amino acid sequence was determined by analysis of peptides generated by digestion of the S-carboxyamido-methylated protein with Achromobacter protease I or cyanogen bromide. The sequence shows a remarkable periodicity of leucine residues, which is homologous to the consensus sequence of a highly diversified protein super-family with a common repetitive module. Thrombin cleavage site was determined to be located at the C-terminal region of GPV by analysis of the products separated by sizing and reversed-phase high performance liquid chromatography. By lectin blot analysis, the existence of mucin-type carbohydrate chains was indicated, as well as the existence of asparagine-linked carbohydrate chains shown by the amino acid sequence analysis. From these data, we report a structural model of GPV that is analogous to glycoprotein Ib.
Shimomura
T
T
Department of Internal Medicine, Hiroshima University, Japan.
Fujimura
K
K
Maehama
S
S
Takemoto
M
M
Oda
K
K
Fujimoto
T
T
Oyama
R
R
Suzuki
M
M
Ichihara-Tanaka
K
K
Titani
K
K
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001792:Blood Platelets / Q000032:analysis*; D006801:Humans; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D010980:Platelet Membrane Glycoproteins / Q000032:analysis / Q000302:isolation & purification*
D000596:Amino Acids; D010446:Peptide Fragments; D010980:Platelet Membrane Glycoproteins