NUCLEOTIDES AND NUCLEOSIDE

BYDR. MARYJANE

INTRODUCTION

• Nucleotides are intracellular molecules having a sugar, base and phosphate.

• The base and sugar only forms nucleoside.

BASES

•BASES: The nitrogenous bases are either pyrimidines or purines.

PYRIMIDINE BASES

• They contain pyrimidine ring. There are 3 pyrimidines that enter in the structure of nucleic acid. They include;

• Uracil• Thymine• Cytosine.

CYTOSINE

URACIL

THYMINE

• The pyrimidine bases cytosine and thymine are found in the structure of DNA.• The pyrimidine bases uracil

and cytosine are found in the structure of RNA.

PURINE BASES• They contain the purine

ring and there are 2 purines that enter in the structure of nucleic acid. They include:

• Adenine• Guanine

ADENINE

GUANINE

• Adenine and guanine are 2 purines which are found in the structure of nucleic acids (DNA and RNA).

• Hypoxanthine, xanthine and uric acid are the end products of adenine and guanine catabolism.

HYPOXANTHINE

URIC ACID

XANTHINE

GOUT

• Is a disease characterized by an increase of uric acid concentration in plasma. This leads to deposition of uric acid in small joints especially that of:

• Big toe causing severe pain• Kidney resulting in kidney stones• Cartilage leading to destruction of cartilage.

SUGARS

• The sugars in the structure of nucleotides are either β-D-Ribofuranose for RNA or β-D-Deoxyribofuranose for DNA.

Nomenclature of different nucleosides and nucleotides

BASE NUCLEOSIDE NUCLEOTIDE

ADENINE (A) ADENOSINE ADENSINE MONOPHOSPHATE (AMP)

GUANINE (G) GUANOSINE GUANOSINE MONOPHOSPHATE (GMP)

XANTHINE (X) XANTHOSINE XANTHOSINE MONOPHOSPHATE (XMP)

HYPOXANTHINE (I) INOSINE INOSINE MONOPHOSPHATE (IMP)

CYTOSINE (C) CYTIDINE CYTIDINE MONOPHOSPHATE (CMP)

URACIL (U) URIDINE URIDINE MONOPHOSPHATE (UMP)

THYMINE (T) THYMIDINE THYMIDINE MONOPHOSPHATE (TMP)