Open AccessEvidence for a prevalent dimorphism in the activation peptide of human coagulation factor IX.
Author(s) -
Royal A. McGraw,
Lisa M. Davis,
Claudia M. Noyes,
Roger L. Lundblad,
Howard W. Roberts,
John B. Graham,
DW Stafford
Publication year - 1985
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.82.9.2847
Subject(s) - threonine , peptide , alanine , peptide sequence , complementary dna , biology , factor ix , amino acid , factor vii , coagulation , biochemistry , microbiology and biotechnology , phosphorylation , gene , serine , medicine
We have independently isolated and characterized cDNA and genomic clones for the human coagulation factor IX. Sequence analysis in both cases indicates that threonine is encoded by the triplet ACT as the third residue of the activation peptide. This is in agreement with some earlier reports but in disagreement with others that show the alanine triplet GCT at this position. The discrepancy can thus be accounted for by natural variation of a single nucleotide in the normal population. Amino acid sequence analyses of activated factor IX from plasma samples of four individuals yielded two cases of alanine and two cases of threonine at the third position of the activation peptide. In factor IX from pooled plasma and in factor IX from a heterozygous individual, however, both alanine and threonine were found. Taken together, the findings show that a prevalent nondeleterious dimorphism exists in the activation peptide of human coagulation factor IX.