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Chapter-23 Nucleotides: Chemistry and Metabolism

BOOK TITLE: Textbook of Biochemistry for Dental Students

Author
1. Vasudevan DM
2. S Sreekumari
3. Vaidyanathan Kannan
ISBN
9789350254882
DOI
10.5005/jp/books/11333_23
Edition
2/e
Publishing Year
2011
Pages
7
Author Affiliations
1. Faculty of Medicine, Amrita Vishwa Vidyapeetham, (Amrita University), Kochi, Kerala, Formerly Principal, College of Medicine, Amrita, Kerala; Formerly, Dean, Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, Amrita Vishwa Vidyapeetham (Deemed University), Cochin, Kerala, E-mail: dmvasudevan@aims.amrita.edu, PG Programs and Research College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India, College of Medicine, Amrita Institute of Medical Sciences, Kochi, Kerala, India; Sikkim Manipal Institute of Medical Sciences, Gangtok, Sikkim, India
2. Jubilee Mission Medical College, Trissur, Kerala, Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India, Government Medical College, Thrissur and Thiruvananthapuram, Kerala, India; Sree Gokulam Medical College and Research Foundation, Thiruvananthapuram, Kerala, India; Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
3. Amrita Institute of Medical Sciences, Kochi, Kerala, India, Pushpagiri Institute of Medical Sciences and Research Centre, Thiruvalla, Kerala, India, Believers Church Medical College and Hospital, Thiruvalla, Kerala, India
Chapter keywords

Abstract

Base + sugar = nucleoside; base + sugar + phosphate = nucleotide. Bases are purines and pyrimidines. Common purines are adenine and guanine. Common pyrimidines are cytosine, uracil and thymine. Adenosine triphosphate (ATP) is the universal energy currency. It contains adenosine + ribose + phosphate + phosphate + phosphate. De novo synthesis of purine nucleotide starts with PRPP (phosphoribosyl pyrophosphate). There are 10 steps in the de novo synthesis of purine. The first step is by phosphoribosyl amido transferase; it is the rate limiting enzyme; it is inhibited by AMP and GMP. Purines are degraded into uric acid. Uric acid level in blood is increased in gout. Pyrimidine ring is produced from carbamoyl phosphate and aspartic acid. The first enzyme in pyrimidine synthesis is carbamoyl phosphate synthase-II (synthase-I is used for urea synthesis). Orotic aciduria results from the deficiency of either OPTase or OMP decarboxylase.

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