ketohexóza

Ketohexóza is a type of monosaccharide, specifically a six-carbon sugar, that contains a ketone group. This functional group is characterized by a carbonyl group (C=O) located at the second carbon atom, hence the prefix "keto-". The general chemical formula for ketohexoses is C6H12O6. Unlike aldoses, which have an aldehyde group at the first carbon atom, ketohexoses have a ketone group at the second carbon atom. This structural difference leads to variations in their chemical properties and biological functions.

Ketohexoses can exist in two isomeric forms due to the presence of a chiral center at the second carbon atom. These isomers are known as D-ketohexoses and L-ketohexoses, depending on the configuration of the hydroxyl groups. The most well-known ketohexose is fructose, which is a common sugar found in fruits and honey. Fructose is a D-ketohexose and is often used in the food industry as a sweetener.

In biological systems, ketohexoses play various roles. They can serve as intermediates in metabolic pathways, such as glycolysis and the pentose phosphate pathway. Additionally, ketohexoses can be converted into other sugars or used as energy sources. The presence of a ketone group in ketohexoses makes them more reactive than aldoses, which can influence their biological activities.

Ketohexoses are also important in the context of carbohydrate chemistry and biochemistry. Their unique structure allows for the formation of various glycosidic bonds, which are crucial for the synthesis of complex carbohydrates and glycoconjugates. Understanding the properties and functions of ketohexoses is essential for studying carbohydrate metabolism, enzyme catalysis, and the structural biology of glycans.