We absorb nucleic acids (DNA and RNA) through digestion in the small intestine, facilitated by enzymes from both the pancreas and the small intestine itself.
Here's a breakdown of the process:
1. Digestion in the Small Intestine
- Dietary nucleic acids, primarily DNA and RNA from the food we consume, enter the small intestine.
- The breakdown begins with the action of pancreatic enzymes:
- Ribonuclease: This enzyme targets and breaks down RNA molecules into smaller fragments.
- Deoxyribonuclease: This enzyme targets and breaks down DNA molecules into smaller fragments.
2. Further Breakdown by Intestinal Enzymes
- The smaller nucleic acid fragments produced by the pancreatic enzymes are further digested by enzymes present in the small intestine. These enzymes include:
- Phosphatases: Remove phosphate groups.
- Nucleosidases: Break down nucleosides into nitrogenous bases (adenine, guanine, cytosine, thymine, uracil) and pentose sugars (ribose or deoxyribose).
- Phosphorylases: Break the bond between the nitrogenous base and the sugar.
3. Absorption of Components
- The final products of nucleic acid digestion – nitrogenous bases, pentose sugars, and phosphate groups – are then absorbed by the cells lining the small intestine (enterocytes).
- These components are absorbed via active transport mechanisms.
- Once absorbed, they can be used by the body for nucleotide synthesis or catabolized for energy.
In summary, the absorption of nucleic acids is a multi-step enzymatic process within the small intestine, resulting in the absorption of nitrogenous bases, sugars, and phosphates that can be utilized by the body.
