Nucleic Acids-Introduction-Classification-Chemistry-Biological Role-Biomole.-Biochem.-B Pharm 2 Sem
32 هزار بار بازدید -
3 سال پیش
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Introduction of Nucleic acidNucleic acid
Introduction of Nucleic acid
Nucleic acid are polymers that consist of nucleotide residues.
Located in nuclei of cell
Hereditary determinants of living organisms
Elemental composition – carbon, hydrogen, oxygen, nitrogen and phosphorus
Classification of Nucleic Acid
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Chemical Nature of Nucleic Acid
Hydrolysis of nucleic acids gives nucleotide, which can be considered the units that make up the polymer. Phosphate esters of nucleosides. A nucleotide consists of three parts:
Heterocyclic base
sugar
phosphoric acids
NUCLEOSIDES: When ribose or 2-deoxyribose is combined with purine or pyrimidine base Nucleoside is formed.
Sugar:
In RNA =nucleotide the sugar is Ribose,
In DNA =nucleotide it is Deoxyribose.
Heterocyclic or Nitrogenous Bases
Present in nucleic acids are divided into two types- Purines and Pyrimidines.
The two Purines present both DNA and RNA are adenine and guanine.
The Pyrimidines cytosine is present in both DNA and RNA, whereas thymine is found in DNA only and Uracil is present in RNA only.
Pyrimidines Bases: Thymine (2,4-dioxy-5-methylpyrimidine),
Cytosine (2-oxy-4-aminopyrimidine) and
Uracil (2,4-dioxypyrimidines).
Purines Bases: The Purines found in nucleic acids are derivatives of a substances, Purine, that does not occur naturally. As indicated by their structures, adenine is 6-amino- purine and guanine is 2-amino-6-oxypurine.
Tautomeric Forms of Purine and Pyrimidine
Tautomerism which expresses wandering tendency of an hydrogen (H) atom involves migration of a proton (H+)from α carbon to carbon oxygen by the following mechanism. The tautomer containing the carbonyl group is designated as the keto or lactam form and the other one having a hydroxyl group attached to a double bond carbon is referred to as the enol or lactim form. this kind of tautomerism is called keto-enol or more appropriately lactam-lactim tautomerism.
Hydrolysis of Nucleic Acid Under Alkaline Condition:
The experiment showed that in the test tube RNA is hydrolysed rapidly under alkaline condition but DNA is not.
It has been found that the 2-hydroxyl group in RNA which is absent in DNA are directly involved in the process.
This explains that RNA are susceptible to alkaline attack but DNA are not.
Principal bases, Nucleosides and Nucleotides
Biological Role of Nucleic acids or Biological Functions of Nucleic acids or Biological Importance of Nucleic acids
ATP, UTP, GTP and CTP
Purine and pyrimidine nucleotides are involve in variety of metabolic functions- energy metabolism, protein metabolism, control of enzyme activity.
Nucleotides are structural components of some coenzymes of B complex vitamins e.g. FAD, NAD.
Sugar derivative of nucleotides namely UDP-glucose participates in the synthesis of glycogen.
Pharmaceutical Useful Synthetic Analogues of Nucleotides
Prepared by altering either the heterocyclic ring or sugar moiety.
These are used chemotherapeutically to control cancer or infections.
Allopurinol: used in the treatment of hyperuricemia and gout.
5-fluorouracil, 6-mercaptopurine, 8-guanine, 3- deoxyuridine, 5- or 6-azauridine, 5- or 6-azacytidine & 5- idouracil are used in treatment of cancer.
Azathioprine is used to suppress immunological rejection during transplantation.
Arabinosyladenine is used for treatment of neurological diseases, viral encephalitis.
Arabinosylcytosine is used in cancer therapy as it interferes with DNA replication.
Zidovudine or AZT & didanosine are sugar modified synthetic nucleotide analogs, used in the treatment of AIDS
#biomolecules b pharm 2nd semester
#biochemistry_b _pharm_2nd_semester_unit 1
Nucleic acid are polymers that consist of nucleotide residues.
Located in nuclei of cell
Hereditary determinants of living organisms
Elemental composition – carbon, hydrogen, oxygen, nitrogen and phosphorus
Classification of Nucleic Acid
Deoxyribonucleic acid (DNA)
Ribonucleic acid (RNA)
Chemical Nature of Nucleic Acid
Hydrolysis of nucleic acids gives nucleotide, which can be considered the units that make up the polymer. Phosphate esters of nucleosides. A nucleotide consists of three parts:
Heterocyclic base
sugar
phosphoric acids
NUCLEOSIDES: When ribose or 2-deoxyribose is combined with purine or pyrimidine base Nucleoside is formed.
Sugar:
In RNA =nucleotide the sugar is Ribose,
In DNA =nucleotide it is Deoxyribose.
Heterocyclic or Nitrogenous Bases
Present in nucleic acids are divided into two types- Purines and Pyrimidines.
The two Purines present both DNA and RNA are adenine and guanine.
The Pyrimidines cytosine is present in both DNA and RNA, whereas thymine is found in DNA only and Uracil is present in RNA only.
Pyrimidines Bases: Thymine (2,4-dioxy-5-methylpyrimidine),
Cytosine (2-oxy-4-aminopyrimidine) and
Uracil (2,4-dioxypyrimidines).
Purines Bases: The Purines found in nucleic acids are derivatives of a substances, Purine, that does not occur naturally. As indicated by their structures, adenine is 6-amino- purine and guanine is 2-amino-6-oxypurine.
Tautomeric Forms of Purine and Pyrimidine
Tautomerism which expresses wandering tendency of an hydrogen (H) atom involves migration of a proton (H+)from α carbon to carbon oxygen by the following mechanism. The tautomer containing the carbonyl group is designated as the keto or lactam form and the other one having a hydroxyl group attached to a double bond carbon is referred to as the enol or lactim form. this kind of tautomerism is called keto-enol or more appropriately lactam-lactim tautomerism.
Hydrolysis of Nucleic Acid Under Alkaline Condition:
The experiment showed that in the test tube RNA is hydrolysed rapidly under alkaline condition but DNA is not.
It has been found that the 2-hydroxyl group in RNA which is absent in DNA are directly involved in the process.
This explains that RNA are susceptible to alkaline attack but DNA are not.
Principal bases, Nucleosides and Nucleotides
Biological Role of Nucleic acids or Biological Functions of Nucleic acids or Biological Importance of Nucleic acids
ATP, UTP, GTP and CTP
Purine and pyrimidine nucleotides are involve in variety of metabolic functions- energy metabolism, protein metabolism, control of enzyme activity.
Nucleotides are structural components of some coenzymes of B complex vitamins e.g. FAD, NAD.
Sugar derivative of nucleotides namely UDP-glucose participates in the synthesis of glycogen.
Pharmaceutical Useful Synthetic Analogues of Nucleotides
Prepared by altering either the heterocyclic ring or sugar moiety.
These are used chemotherapeutically to control cancer or infections.
Allopurinol: used in the treatment of hyperuricemia and gout.
5-fluorouracil, 6-mercaptopurine, 8-guanine, 3- deoxyuridine, 5- or 6-azauridine, 5- or 6-azacytidine & 5- idouracil are used in treatment of cancer.
Azathioprine is used to suppress immunological rejection during transplantation.
Arabinosyladenine is used for treatment of neurological diseases, viral encephalitis.
Arabinosylcytosine is used in cancer therapy as it interferes with DNA replication.
Zidovudine or AZT & didanosine are sugar modified synthetic nucleotide analogs, used in the treatment of AIDS
#biomolecules b pharm 2nd semester
#biochemistry_b _pharm_2nd_semester_unit 1
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