Heptose
Encyclopedia
A heptose is a monosaccharide
with seven carbon
atoms.
They have either an aldehyde
functional group
in position 1 (aldoheptoses) or a ketone
functional group in position 2 (ketoheptoses).
There are few examples of C-7 sugars in nature, among which are:
Ketoheptoses have 4 chiral centers, whereas aldoheptoses have 5.
Monosaccharide
Monosaccharides are the most basic units of biologically important carbohydrates. They are the simplest form of sugar and are usually colorless, water-soluble, crystalline solids. Some monosaccharides have a sweet taste. Examples of monosaccharides include glucose , fructose , galactose, xylose...
with seven carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
atoms.
They have either an aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....
functional group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...
in position 1 (aldoheptoses) or a ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...
functional group in position 2 (ketoheptoses).
There are few examples of C-7 sugars in nature, among which are:
- SedoheptuloseSedoheptuloseSedoheptulose or D-altro-heptulose is a ketoheptose — a monosaccharide with seven carbon atoms and a ketone functional group. It is one of the few heptoses found in nature....
or D-altro-heptulose (a ketose), an early intermediate in lipid ALipid ALipid A is a lipid component of an endotoxin held responsible for toxicity of Gram-negative bacteria. It is the innermost of the three regions of the lipopolysaccharide molecule, and its hydrophobic nature allows it to anchor the LPS to the outer membrane...
biosynthesis - MannoheptuloseMannoheptuloseMannoheptulose is a hexokinase inhibitor. It is a heptose, a monosaccharide with seven carbon atoms. By blocking the enzyme hexokinase, it prevents glucose phosphorylation. As a result, the breakdown of glucose is inhibited. It is found as D-mannoheptulose in avocados....
, found in avocados - L-glycero-D-manno-heptose (an aldose), a late intermediate in lipid ALipid ALipid A is a lipid component of an endotoxin held responsible for toxicity of Gram-negative bacteria. It is the innermost of the three regions of the lipopolysaccharide molecule, and its hydrophobic nature allows it to anchor the LPS to the outer membrane...
biosynthesis.
Ketoheptoses have 4 chiral centers, whereas aldoheptoses have 5.