Detection of vitamin K deficiency by use of an enzyme-linked immunosorbent assay for circulating abnormal prothrombin.
A monoclonal antibody was raised against an abnormal decarboxylated prothrombin by a cell fusion technique. A cell line which produces an IgG1 murine antibody to the abnormal prothrombin, but not to prothrombin, was selected. Using this antibody we developed an enzyme-linked sandwich immunoassay for the abnormal prothrombin. The detection range was 0.5 X 10(-1) approximately 0.5 X 10(-3) micrograms protein of decarboxylated prothrombin and 0.5 approximately 0.5 X 10(-2) micrograms protein of abnormal prothrombin in vitamin K-deficient subjects. This discrepancy is attributable to a heterogeneity of decarboxylated prothrombin, depending on the number of gamma-carboxyglutamic acid residues. The antibody obtained had a higher affinity to a protein possessing less gamma-carboxyglutamic acid residues. The assay system developed may be useful for the detection of vitamin K deficiency, since a severe deficiency may result in less gamma-carboxyglutamic acid residues in the protein.
D015055:1-Carboxyglutamic Acid / Q000032:analysis; D000328:Adult; D000911:Antibodies, Monoclonal; D015415:Biomarkers; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007223:Infant; D011498:Protein Precursors / Q000032:analysis* / Q000276:immunology; D011516:Prothrombin / Q000032:analysis* / Q000276:immunology; D014813:Vitamin K Deficiency / Q000097:blood / Q000175:diagnosis*
D000911:Antibodies, Monoclonal; D015415:Biomarkers; D011498:Protein Precursors; C008208:acarboxyprothrombin; D015055:1-Carboxyglutamic Acid; D011516:Prothrombin