Question

• Discuss the validity of using the glucose standard curve for t

he quantification of glucose plus mannose

Answer 1

Mannose is only an epimer of glucose, i.e. they differ from each other on the configuration of the functional groups at one carbon alone. However, the functional groups present and both are hexoses, monosaccharides so the molecular weights are similar. So, the absorbance values obtained upon reaction of mannose and glucose with any biochemical reagent used to estimate their quantities, is almost the same. Therefore, a standard curve of glucose can be used to quantify glucose plus mannose. The unknown quantity is generally expressed as glucose equivalents.