Title : Amino acid
sequence and posttranslational modifications of human
factor VIIa from plasma and transfected baby hamster kidney cells
Abstract :
- Blood coagulation factor VII is a vitamin K dependent glycoprotein which in its activated form, factor VIIa , participates in the coagulation process by activating factor X and/or factor IX in the presence of Ca2 + and tissue factor
- Three types of potential posttranslational modifications exist in the human factor VIIa molecule, namely, 10 gamma-carboxylated, N-terminally located glutamic acid residues , 1 beta-hydroxylated aspartic acid residue , and 2 N-glycosylated asparagine residues
- In the present study, the amino acid sequence and posttranslational modifications of recombinant factor VIIa as purified from the culture medium of a transfected baby hamster kidney cell line have been compared to human plasma factor VIIa
- By use of HPLC, amino acid analysis, peptide mapping, and automated Edman degradations, the protein backbone of recombinant factor VIIa was found to be identical with human factor VIIa
- Neither recombinant factor VIIa nor human plasma factor VIIa was found to contain beta-hydroxyaspartic acid
- In human plasma factor VIIa , the 10 N-terminally located glutamic acid residues were found to be fully gamma-carboxylated whereas 9 full and 1 partial gamma-carboxylated residues were found in the corresponding positions of the recombinant factor VIIa molecule
- Asparagine residues 145 and 322 were found to be fully N-glycosylated in human plasma factor VIIa
- In the recombinant factor VIIa , asparagine residue 322 was fully glycosylated whereas asparagine residue 145 was only partially (approximately 66%) glycosylated
- Besides minor differences in the sialic acid and fucose contents, the overall carbohydrate compositions were nearly identical in recombinant factor VIIa and human plasma factor VIIa
- (ABSTRACT TRUNCATED AT 250 WORDS