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A new principle for measurement of cobalamin and corrinoids, used for studies of cobalamin analogs on serum haptocorrin.
Clin Chem 2009; 55(5):1002-10CC

Abstract

BACKGROUND

Transcobalamin (TC) and haptocorrin (HC) are serum corrinoid-binding proteins. We developed new methods for measurement of the corrinoids bound to HC and TC.

METHODS

TC (n = 10) or HC (n = 138) was immunoprecipitated, and corrinoids were released by enzymatic degradation [subtilisin Carlsberg (EC 3.4.21.62)] of the binding proteins. Binding of the released corrinoids to added unsaturated TC (apoTC) or HC (apoHC) created holoTC (as measure of cobalamins) and holoHC (as measure of corrinoids). holoTC and holoHC were measured by use of ELISA. The amounts of analogs were calculated as the difference between corrinoids and cobalamins. Corrinoids extracted from HC were separated with HPLC after addition of potassium cyanide (n = 3).

RESULTS

The corrinoid- and cobalamin-specific assays had a positive linear relation between analyte concentration and assay signal, detection limits of 8 and 4 pmol/L, and imprecision values (CV) of <or=10% and <or=13% for concentrations between 45-200 and 12-115 pmol/L, respectively. No analogs were bound to serum TC, whereas the mean (95% reference range) for analogs present on HC was 245 (100-380) pmol/L. On HPLC a substantial amount of the analogs showed elution patterns similar to those of dicyanocobinamide.

CONCLUSIONS

Our methods for measurement of unmodified corrinoids in serum demonstrate that HC carries cobalamin analogs not recognized by TC, and that on HPLC a substantial part of these analogs elute similarly to cobinamide.

Authors+Show Affiliations

Department of Clinical Biochemistry, AS, Aarhus University Hospital, Aarhus, Denmark. tore.forsingdal.hardlei@ki.au.dkNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19299543

Citation

Hardlei, Tore Forsingdal, and Ebba Nexo. "A New Principle for Measurement of Cobalamin and Corrinoids, Used for Studies of Cobalamin Analogs On Serum Haptocorrin." Clinical Chemistry, vol. 55, no. 5, 2009, pp. 1002-10.
Hardlei TF, Nexo E. A new principle for measurement of cobalamin and corrinoids, used for studies of cobalamin analogs on serum haptocorrin. Clin Chem. 2009;55(5):1002-10.
Hardlei, T. F., & Nexo, E. (2009). A new principle for measurement of cobalamin and corrinoids, used for studies of cobalamin analogs on serum haptocorrin. Clinical Chemistry, 55(5), pp. 1002-10. doi:10.1373/clinchem.2008.114132.
Hardlei TF, Nexo E. A New Principle for Measurement of Cobalamin and Corrinoids, Used for Studies of Cobalamin Analogs On Serum Haptocorrin. Clin Chem. 2009;55(5):1002-10. PubMed PMID: 19299543.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A new principle for measurement of cobalamin and corrinoids, used for studies of cobalamin analogs on serum haptocorrin. AU - Hardlei,Tore Forsingdal, AU - Nexo,Ebba, Y1 - 2009/03/19/ PY - 2009/3/21/entrez PY - 2009/3/21/pubmed PY - 2009/6/12/medline SP - 1002 EP - 10 JF - Clinical chemistry JO - Clin. Chem. VL - 55 IS - 5 N2 - BACKGROUND: Transcobalamin (TC) and haptocorrin (HC) are serum corrinoid-binding proteins. We developed new methods for measurement of the corrinoids bound to HC and TC. METHODS: TC (n = 10) or HC (n = 138) was immunoprecipitated, and corrinoids were released by enzymatic degradation [subtilisin Carlsberg (EC 3.4.21.62)] of the binding proteins. Binding of the released corrinoids to added unsaturated TC (apoTC) or HC (apoHC) created holoTC (as measure of cobalamins) and holoHC (as measure of corrinoids). holoTC and holoHC were measured by use of ELISA. The amounts of analogs were calculated as the difference between corrinoids and cobalamins. Corrinoids extracted from HC were separated with HPLC after addition of potassium cyanide (n = 3). RESULTS: The corrinoid- and cobalamin-specific assays had a positive linear relation between analyte concentration and assay signal, detection limits of 8 and 4 pmol/L, and imprecision values (CV) of <or=10% and <or=13% for concentrations between 45-200 and 12-115 pmol/L, respectively. No analogs were bound to serum TC, whereas the mean (95% reference range) for analogs present on HC was 245 (100-380) pmol/L. On HPLC a substantial amount of the analogs showed elution patterns similar to those of dicyanocobinamide. CONCLUSIONS: Our methods for measurement of unmodified corrinoids in serum demonstrate that HC carries cobalamin analogs not recognized by TC, and that on HPLC a substantial part of these analogs elute similarly to cobinamide. SN - 1530-8561 UR - https://www.unboundmedicine.com/medline/citation/19299543/A_new_principle_for_measurement_of_cobalamin_and_corrinoids_used_for_studies_of_cobalamin_analogs_on_serum_haptocorrin_ L2 - http://www.clinchem.org/cgi/pmidlookup?view=long&amp;pmid=19299543 DB - PRIME DP - Unbound Medicine ER -