Determination of glycated proteins in biological samples based on colorimetry of 2-keto-glucose released with hydrazine.
We developed a novel method for measuring glycated (glc) proteins in biological samples, based on the colorimetry of 2-keto-glucose which is released from the glc protein (ketoamine) on heating with hydrazine. The ketoamine-induced coloration remained constant at room temperature (25-27 degrees C) for 1 h. The method gave reliable precision and accuracy. However, high concentrations of serum pigments caused positive interference, suggesting that hemolytic or hyperbilirubinemic serum would give false-positive results. The concentration of glc protein in clinical serum samples measured by the present method (y) correlated well with those (fructosamine values, x) measured by the nitroblue tetrazolium-reducing method: y = 1.27x-1.69 (r = 0.92, n = 93). The concentrations (microM, mean +/- S.D.) of glc protein in sera from normal and diabetic subjects were 275 +/- 37 (n = 32) and 403 +/- 98 (n = 32), respectively, and the concentrations (nmol/mg hair, mean +/- S.D.) of glc protein in back hairs from non-diabetic and diabetic rats were 3.7 +/- 0.3 (n = 10) and 8.6 +/- 1.5 (n = 10), respectively. Thus, the technique gave reasonable concentrations of glc proteins in humans and rats with diabetes mellitus, indicating it to be reliable and diagnostically useful.
Diagnostic Science Department, Shionogi & Co., Ltd. Settsu, Japan.
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Kobayashi
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Yoshimoto
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K
Hirauchi
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K
Uchida
D000328:Adult; D000368:Aged; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D003124:Colorimetry; D003920:Diabetes Mellitus / Q000235:genetics / Q000378:metabolism; D005260:Female; D019270:Fructosamine; D005947:Glucose / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D006442:Glycated Hemoglobin / Q000032:analysis; D006023:Glycoproteins / Q000032:analysis* / Q000097:blood; D006197:Hair / Q000737:chemistry; D006461:Hemolysis; D006595:Hexosamines / Q000097:blood; D006801:Humans; D006834:Hydrazines / Q000737:chemistry*; D006932:Hyperbilirubinemia / Q000097:blood; D007661:Ketoses; D008297:Male; D008875:Middle Aged; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000032:analysis
D001786:Blood Glucose; D019270:Fructosamine; D005947:Glucose; D006442:Glycated Hemoglobin; D006023:Glycoproteins; D006595:Hexosamines; D006834:Hydrazines; D007661:Ketoses; D012709:Serum Albumin; C017022:glucosone