title: Cobalamin analogues in humans: a study on maternal and cord blood.
abstract: BACKGROUND
  Haptocorrin (HC) carries cobalamin analogues (CorA), but whether CorA are produced in the body is unknown. All cobalamins (Cbl) to the foetus are delivered by the Cbl-specific protein transcobalamin (TC), and therefore analysis of cord serum for CorA may help to clarify the origin of CorA.
  
  
  METHODS
  HC-CorA were quantified in paired samples of cord serum from newborns and serum from mothers (n = 69).
  
  
  RESULTS
  The CorA-concentration was higher in cord serum (median = 380, range: 41-780 pmol/L) than in serum from the mothers (median = 160, range: 64-330 pmol/L), (p<0.0001). HPLC-analysis showed CorA-peaks with retention times of 13.5, 14,5 and 16.5 min in samples from both the mother and cord serum. The peak with retention time 16.5 min constituted 24% (mother) and 45% (cord serum) of the total amount CorA, and eluted as does dicyanocobinamide.
  
  
  CONCLUSIONS
  Our results support that CorA in the human body are derived from Cbl.
authors.affiliation: Department of Clinical Biochemistry, Aarhus University Hospital, Aarhus, Denmark. torehard@rm.dk
authors.forename: Tore Forsingdal
authors.initials: TF
authors.lastname: Hardlei
authors.forename: Rima
authors.initials: R
authors.lastname: Obeid
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Herrmann
authors.forename: Ebba
authors.initials: E
authors.lastname: Nexo
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy / Q000097:blood*; D014155:Transcobalamins / Q000032:analysis*; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D014155:Transcobalamins; D014805:Vitamin B 12