Abstract
Cobalamins in human serum were separated using HPLC gradient system after extraction with N- ethylmaleimide and citrate-phosphate buffer system. Each cobalamin analogue in the elute was con verted to cyanocobalamin (CN-Cbl) by the addition of KCN, and the cobalamin contents were deter mined by a microbiological assay with Lactobacillus delbrueckii subsp. lactis ATCC 7830. This method was applied to determination of serum cobalamin analogues in healthy volunteers. The ratios of each cobalamin analogue in the serum of the male volunteers were methylcobalamin (CH3-Cbl): 66.5 ± 12.3%, hydroxocobalamin (OH-Cbl): 17.1 ± 9.4% and adenosylcobalamin (Ado Cbl) : 14.1 ± 5.8%. The ratios for female volunteers were CH_3-Cbl: 72.4 ± 9.3%, OH-Cbl: 12.3 ± 8.6% and AdoCbl: 9.8 ± 5.8%.
