Glycosylated plasma protein measurement by a semi-automated method

A semi-automated method for determination of glycosylation of plasma proteins using the thiobarbituric acid method is described. Plasma samples (100 microL) and a plasma pool used as a secondary standard were incubated in 0.3 M oxalic acid at 100 degrees C for exactly 2 h. The hydroxymethyl furfural released and the total protein were measured concurrently on a Technicon AAII Autoanalyzer. Addition of 10 or 20 mmol glucose to plasma samples caused a minimal increase in the measured glycosylated protein. Within-batch and between-batch coefficients of variation were 3.1% and 4.9% respectively. The mean glycosylated protein levels for 52 normals and 48 maturity-onset diabetics were (+/- 1SD) 0.96 +/- 0.13 and 1.75 +/- 0.32 nmol HMF/mg protein/2 h incubation.