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Glycated hemoglobin can be degraded by proteolytic enzyme(s) in the
erythrocyte. The enzyme(s) co-elutes with glycated hemoglobin when the
latter is separated from erythrocyte lysates using the cation-exchanger Bio
Rex-70. A further purification of the Bio Rex eluant on DEAE Sephadex A-50
separated the enzyme(s) from glycated hemoglobin. Studies with the Bio Rex
eluant showed that degradation of glycated hemoglobin is maximum at 37^oC
at pH 8.6. Proteolytic degradation is inhibited by 5 mM N-ethylmaleimide
(NEM), 5 mM ethylenediamine tetraacetic acid (EDTA) and 0.6 mM
n-p-tosyl-L-lysine choromethyl ketone (TLCK) (100, 87 and 76% inhibition
respectively). This study also examines the possibility that oxidative
damage to glycated hemoglobin increases its susceptibility to proteolytic
degradation. When incubated with various anti-oxidants like DTPA, uric
acid, mannitol and butylated hydroxy toluene (BHT), proteolytic degradation
of glycated hemoglobin decreased by 66.1, 50.7 and 38% respectively.
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