Glucose: Most Important One Carbohydrate In Human Body

STRUCTURE OF GLUCOSE

Introduction to glucose:

 There are many types of carbohydrates but the most important one carbohydrate in human body is glucose (C6H12O6). Glucose is also termed as monosaccharide due to the fact that it forms one simple building block of more complicated carbohydrates like starch, glycogen, maltose, sucrose, lactose etc. It is also known as dextrose due to its occurrence in optically active dextro-rotatory isomers [1]. The name "glucose" derived from the Greek word which means "sweet wine, must". The suffix "-ose" indicate that a glucose is a carbohydrate [3].

 The most common and abundant source of glucose is in sweet fruits, honey and grapes (20-30%). It is also an important constituent of human blood. Under normal

Starch is the storage form in plants and glycogen is the storage form of glucose in animals and in animals as glycogen, for times when the organism will need it [1].

 The structure of glucose has following components[1]: 1. There are 2 basic functional groups: one of them is aldehyde and other is hydroxyl groups. Because of the presence of these two polar functional groups, glucose (and other monosaccharides) is highly soluble in water (1.5 g/mL at 25 ºC).

2. There are four chiral carbons or chiral centers in linear structure of a glucose

And these 2 epimeric forms after oxidation yields 2 optically active dicarboxylic acids. This is possible only for the structure II. So, structure IV is also eliminated. Proceeding similarly you will find that if D-arabinose had configuration IV, of the two dicarboxylic acids derived from it, one would be meso and one asymmetric (optically active). Hence D-arabinose has the configuration II. 4. Ruff degradation of D-glucose and D-mannose produces D-arabinose in each case:

Ruff degradation is the process of the destruction of below CHO consequently, the configuration of the two aldo-hexoses, D-glucose and D-mannose, can be derived by adding a new CHOH below CHO in form II of D-arabinose. For this reason, D-glucose has configuration V or VI. 5. D-glucose and L-glucose yield the same carboxylic acids:

There is also another sugar which yield same carboxylic acid as yield by the oxidation of D-glucose. This shows that these two sugars differ only with the respect of the position of the terminal groups (CHO and CH2OH groups). Consequently, the exchange of the terminal groups in D-glucose should be able to give different aldo-hexose (L-glucose). Let us now examine configurationally formulas V or VI (one of which is D-glucose) from this