Enhanced nonenzymatic glucosylation of human serum albumin in diabetes mellitus.

Abstract

Use of an ion exchange chromatographic method and a calorimetric method with thiobarbituric acid showed that levels of nonenzymatically glucosylated serum albumin were increased in patients with poorly controlled diabetes mellitus compared to controls. The two methods correlated well (r = 0.99) and clearly discriminated between normal and poorly controlled diabetic populations. The levels of glycosylated hemoglobin were also measured in both populations.Several patients apparently in good control based on glycosylated hemoglobin measurements were found to have increased levels of glucosylated albumin. Because albumin has a shorter circulating half-life than does the human erythrocyte, the plasma concentration of glucosylated albumin should be expected to reflect short-term control of hyperglycemia in diabetes. The studies reported here suggest that the level of glucosylated albumin may indeed be a sensitive indicator of moderate hyperglycemia and of early glucose intolerance. Recent studies showed that plasma proteins are glucosylated nonenzymatically by glucose in vitro (1). Glucosylated albumin was isolated from normal human serum by chromatography on CM-cellulose and accounted for about 8% of the total circulating albumin in man. The nonenzymatic glucosylation of albumin appears to proceed through Schiff base formation between the aldehyde form of the sugar and free amino groups in protein, followed by Amadori rearrangement to a ketoamine derivative (Fig.

Performance characteristics and clinical utility of an enzymatic method for the measurement of glycated albumin in plasma

“…Indeed, the concentration of GA in serum can be measured, as in the case of glycated hemoglobin, on the basis of different principles, such as affinity chromatography [7,8], ion exchange liquid chromatography [9,10], colorimetry [11,12] and immunochemistry [13,14]. However, all these methods suffer from a number of disadvantages, namely, poor precision and long processing times.…”

Association of serum glycated albumin to haemoglobin A1C ratio with hepatic function tests in patients with chronic liver disease

“…7 As the half-life of albumin is about 17 days, shorter than that of erythrocytes, GA is thought to reflect short-term plasma glucose levels (about 2 weeks). While GA measurements are unaffected by abnormal haemoglobin metabolism, 7 they are shown to be influenced by several diseases accompanied by abnormal albumin metabolism, such as nephrotic syndrome, thyroid dysfunction and glucocorticoid administration. As a result, GA levels in patients with such diseases do not properly indicate the status of glycaemic control.…”

Affinity Chromatography: A Precise Method for Glycosylated Albumin Estimation

“…Two millilitres of this slurry (1 mL gel) were added to a mini-column (Pierce and Warriner) and allowed to settle. The columns were equilibrated using 10 mL wash buffer (250 mmol/L ammonium acetate, 50 mmol/L magnesium chloride and 3 mmoVL sodium azide; pH adjusted to 8,8). A 100 ul, aliquot of the diluted plasma was added to the top of the column and allowed to pass into the gel, 4·9 mL of wash buffer was then added, and when this had passed into the column a further 5·0 mL wash buffer was added.…”

“…Most attention has been given to the glycosylation of serum alburnin.v" which has a shorter half-life than haemoglobin, and several authors have proposed that the level of glycosylated albumin would provide a better indicator of short-term glucose control. [7][8][9][10] Mallia et al II synthesised a gel consisting of m-aminophenylboronic acid which selectively Correspondence: W G John.…”