Effect of thiols on fructosamine assay.
Fresh human serum, gGAPDH and beta-mercaptoethanol were used to examine the effect of thiols on fructosamine assay. The kinetics of the reaction with both fresh human serum and gGAPDH displayed biphasic behaviour (fast and slow). When the thiols were modified with IAA, the kinetics only demonstrated the slow phase. Since the absorbance increase in the interval from 9 to 10 min was used in the fructosamine assay of glycated human serum we studied the effect of thiols on that measurement. In the case of gGAPDH, the value was approximately one-half of the original after thiol modification, suggesting thiol interference. Nevertheless, gGAPDH may contain a fructosamine structure. beta-Mercaptoethanol itself gave a strong positive result in the fructosamine assay. Hence, thiol groups on glycated proteins should be modified before doing a fructosamine assay because of their substantial interference.
Liu
W
W
Laboratory of Molecular Neurobiology and Developmental Biology, Academia Sinica, Beijing, P.R.. China.
He
R
R
D001769:Blood / Q000378:metabolism; D004228:Dithionitrobenzoic Acid / Q000378:metabolism / Q000494:pharmacology; D019270:Fructosamine / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008623:Mercaptoethanol / Q000494:pharmacology; D009580:Nitroblue Tetrazolium / Q000378:metabolism; D012709:Serum Albumin / Q000032:analysis / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism*
D012709:Serum Albumin; D013438:Sulfhydryl Compounds; D009580:Nitroblue Tetrazolium; D019270:Fructosamine; D008623:Mercaptoethanol; D004228:Dithionitrobenzoic Acid; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases