Distribution of endogenous cobalamin between the transcobalamins in various mammals.
1. Plasma samples from ten mammals were chromatographed on Sephadex G-200 columns and the total cobalamin content of each fraction was determined. 2. Unlike the situation in man, the bulk of the endogenous plasma cobalamin was found attached to a transcobalamin II-like protein in all ten animals. Transcobalamin 0 carried between 3 and 20% and this proportion appeared to be inversely related to the plasma total cobalamin. No endogenous cobalamin peak corresponding to transcobalamin I was detected in any species, though in the rabbit 5.3% of the plasma total cobalamin was attached to a protein of apparent molecular weight 176 000.
D000818:Animals; D001665:Binding Sites; D001798:Blood Proteins / Q000302:isolation & purification*; D002415:Cats; D002850:Chromatography, Gel; D004285:Dogs; D004901:Erythrocebus patas; D006168:Guinea Pigs; D000882:Haplorhini; D006801:Humans; D010215:Papio; D011817:Rabbits; D051381:Rats; D012756:Sheep; D014155:Transcobalamins / Q000302:isolation & purification*; D014805:Vitamin B 12 / Q000097:blood*
D001798:Blood Proteins; D014155:Transcobalamins; D014805:Vitamin B 12