title: A competitive enzyme-linked ligand sorbent assay (ELLSA) for quantitation of folates.
abstract: An enzyme-linked ligand sorbent assay (ELLSA) for quantitation of folates is described. The method involves the following steps: (a) folate complexed to bovine serum albumin is adsorbed onto microtiter plates; (b) added folates compete with immobilized folate for binding to added biotinylated folate-binding protein; (c) biotinylated folate-binding protein bound to immobilized folate is detected after binding of avidin-alkaline phosphatase. The specificity of ELLSA is similar to that of conventional radioisotope dilution methods, and the sensitivity is high (lower limit of detection 20 fmol/sample). Quantitation of folates in erythrocyte lysates from 43 persons was performed by ELLSA. The results correlated fairly well with those obtained by the conventional radioisotope dilution method.
authors.affiliation: Department of Clinical Chemistry, Central Hospital Hillerød, Denmark.
authors.forename: S I
authors.initials: SI
authors.lastname: Hansen
authors.forename: J
authors.initials: J
authors.lastname: Holm
mesh_terms: D000469:Alkaline Phosphatase; D001360:Avidin; D001665:Binding Sites; D001667:Binding, Competitive; D001710:Biotin / Q000032:analysis; D002352:Carrier Proteins; D004912:Erythrocytes / Q000032:analysis; D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid / Q000031:analogs & derivatives* / Q000032:analysis*; D006801:Humans; D008024:Ligands; D011869:Radioligand Assay; D011956:Receptors, Cell Surface; D012710:Serum Albumin, Bovine / Q000032:analysis
chemical_list: D002352:Carrier Proteins; D058973:Folate Receptors, GPI-Anchored; D008024:Ligands; D011956:Receptors, Cell Surface; D001360:Avidin; D012710:Serum Albumin, Bovine; D001710:Biotin; D005492:Folic Acid; D000469:Alkaline Phosphatase