This document describes the hydrolysis of nucleic acids through acid-catalyzed and base-catalyzed hydrolysis. It provides objectives, theories, and results of qualitative tests performed on DNA and RNA samples and their hydrolysates. Base-catalyzed hydrolysis occurs only in RNA, yielding nucleosides, while DNA remains stable. Acid hydrolysis yields purine and pyrimidine bases and phosphoric acid. Though errors were made, the experiments helped understand nucleic acid hydrolysis and how to differentiate hydrolyzed and unhydrolyzed nucleic acids using qualitative tests.

1. HYDROLYSIS OF
NUCLEIC ACIDS
Group 8

2. Objectives
• To be able to prepare a hydrolyzed and unhydrolyzed DNA and RNA
• To be able to perform qualitative tests to determine the characteristics of nucleic
acid present

3. THEORIES

4. Hydrolysis
• Breaking of a bond in a molecule using water.
• Site of cleavage: sugar, phosphate backbone, or in the base
• Result: purine and pyrimidine bases, oligonucleotide, nucleosides, ribose or
deoxyribose, and phosphate.

5. Base-catalyzed hydrolysis
• Occurs in RNA
• Hydroxyl ion assist a
nucleophilic attack on the 2’
hydroxyl group on the
phosphorus
• yields intermediate cyclic-
2’,3’-phosphonucleosides
that hydrolyze to nucleoside-
2’-phosphates and
nucleoside-3’- phosphates
• UNSTABLE
• Use of water to stabilize
forming 2’ or 3’ nucleoside
• Stable in DNA

6. Acid-catalysed Hydrolysis
• Causes depurination
• Cleaves the purine N-
glycosyl bonds
• Adenine and guanine are
liberated and apurinic site
remains.
• Some phosphodiester bond
are cleaved
• Much harsher and acidic is
required to remove
pyrimidine N-glycosides

7. QUALITATIVETEST
DATA

8. DNA
Test Control DNA Acid Hydrolysate Base Hydrolysate
Benedict’sTest Sky blue Sky blue Sky blue Sky blue
OrcinolTest Rusty brown Light brown Yellow brown
Deoxyribose White sol’n with
brown ppt
Red sol’n with
brown ppt
White sol’n with
brown ppt.
Purine bases Cloudy lavender to
clear solution with
white ppt
Clear solution with
White precipitate
Clear sol’n with
brown ppt
Uracil and
Cytosine
clear solution More cloudy Bright yellow to
clear
solution(Ba(OH)2
BiuretTest Light blue Light blue Light blue
XanthoproteicTest Light yellow Clear solution Light yellow
Inorganic
Phosphate

9. RNA
Test RNA Acid Hydrolysate Base Hydrolysate
Benedict’sTest Sky blue Apple green Sky blue
OrcinolTest Dark bue-green Dark green with black
particles solution
Dark blue-green
Deoxyribose White cloudy with brown
ppt
Red solution with brown
ppt
Layer of orange, white
and brown solutionwith
brown ppt.
Purine bases Cloudy dirty white sol’n Light pink sol’n with
brown ppt
Clear sol’n with black ppt
Uracil and Cytosine More cloudy Cloudy white cloudy white
BiuretTest Light purple Light purple Light blue
XanthoproteicTest Bright yellow Light yellow Bright yellow
Inorganic Phosphate

10. sample

11. Benedict’sTest

12. Orcinol test

13. Test for deoxyribose

14. Test for Purine bases

15. Test for uracil and cytosine

16. Biuret test

17. Xanthoproteic test

18. ANSWERSTO
QUESTIONS

19. How can intact DNA be obtained from a
solution of DNA and RNA
• Dna could be obtained from a solution of DNA and RNA by using
a base-catalyzed hydrolysis, since in alkaline solution RNA is
destabilized forming nucleosides while the DNA remains stable
and intact.

20. Based on the qualitative test, How can you
differentiate hydrolyzed from unhydrolyzed
RNA
• Hydrolized Rna is positive for orcinol test, test for purine bases, biuret test,
xanthoproteic test.
-acid-catalalyzed hydrolysis: presence of pentoses, pyrimidines, and
phosphoric acid
- base-catalysed hydrolysis: only for pentoses and pyrimidines.
• Unhydrolized Rna is only positive for phosphate test.

21. Based on this experimental result, do you
think you obtained pure RNA from yeast?Why
orWhy not?
• We were not able to obtain pure Rna from yeast because of the positive result
from our xanthoproteic and biuret tests

22. Based on these experimental result, do you
think you obtained pure DNA from onion?
Why or why not?
• We were not able to obtain pure DNA because of the positive test of
xanthoproteic on our DNA samples.

23. CONCLUSION

24. • Base-catalysed hydrolysis occurs only in RNA
• Acid hydrolysis of nucleic acids yeilds purines, pyrimidine bases and phosphoric
acid
• Despite the errors in the hydrolysis and qualitative test experiment we have
understood the nucleic acid hydrolysis

25. Reference:
• http://www.scribd.com/doc/38672208/Hydrolysis-of-Nucleic-Acids#scribd
• http://www.chem.uky.edu/courses/che554/5_MolBio/NucleicAcidTechnologyIntro
Chpt.pdf