Deoxyribose is a 5-carbon monosaccharide (pentose) that is formed from ribose when it loses one oxygen atom. The empirical chemical formula for deoxyribose is C5H10O4, and due to the loss of an oxygen atom, it does not agree with the general formula for monosaccharides (CH2O) , where n is an integer.
Physical and chemical properties
The linear formula for deoxyribose can be represented as follows: H-(C=O)–(CH2)–(CHOH)3-H. However, it also exists in the form of a closed ring of carbon atoms.
Deoxyribose is a colorless solid that is odorless and highly soluble in water. Its molecular weight is 134.13 g/mol, melting point 91 °C. It is obtained from ribose-5-phosphate due to the action of appropriate enzymes during the reduction chemical reaction.
The difference between ribose and deoxyribose
As already mentioned and as the name suggests, deoxyribose is a chemical compound whose atomic composition differs from that of ribose by only one oxygen atom. As shownin the figure below, deoxyribose does not have an OH hydroxyl group on its second carbon atom.
Deoxyribose is part of the DNA (deoxyribonucleic acid) chain, while ribose is part of the RNA (ribonucleic acid) chain.
It is interesting to note that the monosaccharides arabinose and ribose are stereoisomers, that is, they differ in spatial arrangement relative to the plane of the OH group ring near the 2nd carbon atom. Deoxyarabinose and deoxyribose are the same compound, but the second name is used because this molecule is derived from ribose.
Deoxyribose and genetic information
Because deoxyribose is part of the DNA chain, it plays an important biological role. DNA - the source of genetic information, consists of nucleotides, which include deoxyribose. Deoxyribose molecules link one nucleotide to another in the DNA chain through phosphate groups.
The absence of the OH hydroxyl group in deoxyribose has been found to give mechanical flexibility to the entire DNA chain compared to RNA, which in turn allows the DNA molecule to form a double strand and be compact inside the cell nucleus.
In addition, due to the flexibility of bonds between nucleotides formed by deoxyribose molecules and phosphate groups, the DNA chain is much longer than RNA. This fact makes it possible to encode genetic information with high density.
