Presence of cobalamin analogues in animal tissues

We report the results of similar studies performed with various animal tissues from which it has been possible to obtain larger quantities of Cbl

H. Kondo; F. Kolhouse; R. H. Allen

2006

Scholarcy highlights

  • Cobalamin has been extracted and isolated from a number of animal tissues by using reverse-affinity chromatography on R protein-Sepharose followed by adsorption to and elution from charcoal-coated agarose and paper chromatography
  • We have covalently attached R protein to Sepharose and have shown that this affinity adsorbent can be utilized to isolate Cbl and Cbl analogues from bacterial lysates in a single step. We have utilized this technique to isolate Cbl from pooled normal human plasma. When this Cbl was fractionated by paper chromatography and assayed for Cbl with a radioisotope dilution assay using R protein, a number of slow and fast moving peaks were observed in addition to the major peak which coincided with that of crystalline Cbl
  • In order to provide further evidence for the presence of Cbl analogues in animal tissues, endogenous Cbl was isolated from 1.5 kg of rabbit kidney by using a modified procedure in which the heat step was omitted-i.e., only non-protein-bound t With commercial preparations ofCbl, only 93-97% of the radioactivity cochromatographed with crystalline Cbi during paper chromatography
  • Fraction D was indistinguishable from crystalline Cbl on the basis of its mobility during paper chromatography in solvents I and II, its affinity for human R protein, transcobalamin II, and intrinsic factor, and its ability to promote the growth of E. gracilis and L. leichmannii
  • The present study provides similar evidence that a number of Cbl analogues are present in various animal tissues
  • It provides direct evidence for the presence of Cbl analogues in animal tissues because we have shown that the Cbl analogue fractions isolated from rabbit kidney contain cobalt; have decreased but definite affinities for human R protein, transcobalamin II, and IF compared to Cbl, and have decreased but definite growthpromoting activities for E. gracilis and L. leichmannii
  • This could explain the presence of Cbl analogues in human, rabbit, bovine, and porcine tissues and could explain their presence in oysters and sole fillets because large amounts of animal wastes are discharged into the ocean

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