title: Quantification of the N-terminal propeptide of human procollagen type I (PINP): comparison of ELISA and RIA with respect to different molecular forms.
abstract: This paper compares the results of procollagen type I N-terminal propeptide (PINP) quantification by radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA). PINP in serum from a patient with uremic hyperparathyroidism was measured in RIA and ELISA to 20 micrograms l-1 and 116 micrograms l-1 and the corresponding concentrations in dialysis fluid were 94.5 micrograms l-1 and 140 micrograms l-1, respectively. PINP antigen appears in two distinct peaks following size chromatography and the two peak fractions display immunological identity and identical M(r)'s (27 kDa: SDS-PAGE). Analysis of fractions from size separated amniotic fluid, serum and dialysis fluid demonstrated that the RIA failed to measure the low molecular weight form of PINP. However, the anti-PINP supplied with the RIA-kit and the anti-PINP applied in the ELISA reacted equally well with both molecular forms of PINP when analysed in a direct ELISA. It is concluded that the major difference in the ELISA and RIA results is due to assay efficacy with respect to the low molecular weight form of PINP.
authors.affiliation: Department of Medical Microbiology, University of Odense, Denmark.
authors.forename: C H
authors.initials: CH
authors.lastname: Jensen
authors.forename: M
authors.initials: M
authors.lastname: Hansen
authors.forename: J
authors.initials: J
authors.lastname: Brandt
authors.forename: H B
authors.initials: HB
authors.lastname: Rasmussen
authors.forename: P B
authors.initials: PB
authors.lastname: Jensen
authors.forename: B
authors.initials: B
authors.lastname: Teisner
mesh_terms: D000653:Amniotic Fluid / Q000737:chemistry; D000906:Antibodies; D000918:Antibody Specificity; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000150:complications; D010446:Peptide Fragments / Q000032:analysis* / Q000097:blood / Q000276:immunology; D011347:Procollagen / Q000032:analysis* / Q000097:blood / Q000276:immunology; D011863:Radioimmunoassay; D014511:Uremia / Q000097:blood / Q000150:complications
chemical_list: D000906:Antibodies; D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide