Further identification of the nature and linkage of the carbohydrate in hemoglobin A1c

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Abstract

We have found that Hb A1c contains neutral sugars which are only partially hydrolyzed from the N-termini of β chains. In both normal and diabetic Hb A1c, 0.2–0.3 equivalents of hexose were released, composed primarily of glucose and mannose in a 3:1 ratio. When Hb A1c was reduced with 3HNa BH4 and then treated with periodic acid, most of the radioactivity was recovered as 3H-formic acid with much lesser amounts of 3H-formaldehyde. From these results, we propose that in the red cell, glucose binds to the α-amino position of hemoglobin β-chains (valine) in an aldimine (Schiff base) linkage. This aldimine can then partially rearrange in a reversible manner to form a ketoamine linkage which is stable to acid hydrolysis. This Amadori-type rearrangement accounts for the formation of mannose, the C-2 epimer of glucose, as well as the inability to demonstrate 3HNa BH4 reduction at the C-1 position.

References (15)

  • R.M. Bookchin et al.

    Biochem. Biophys. Res. Comm

    (1968)
  • S. Rahbar

    Clin. Chim. Acta

    (1968)
  • S. Rahbar et al.

    Biochem. Biophys. Res. Comm

    (1969)
  • R.G. Spiro
  • J.E. Hodge

    Advances in Carbohydrate Chemistry

    (1955)
  • D.W. Allen et al.

    J. Am. Chem. Soc

    (1958)
  • W.R. Holmquist et al.

    Biochemistry

    (1966)
There are more references available in the full text version of this article.

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