Concept explainers
To determine: The positions in the purine ring of a purine
Introduction:
There are two types of nitrogenous bases: purines and pyrimidines. Adenine and guanine are the purine bases with double ring structures. Cytosine and thymine are the pyrimidines bases that have single ring structure. These bases pair with their complementary bases and form a nucleotide sequence through hydrogen bonding.

Explanation of Solution
Explanation:
Adenine is linked to thymine with double hydrogen bond and guanine is linked to cytosine with triple hydrogen bond. The two nucleotides are joined together by the phosphodiester bond.
Purine is a structure that contains nine member ring which is made up of a imidazole ring along with a pyrimidine ring. In adenine amino group present at the sixth position along with first position’s nitrogen is involved in Watson-Crick base pairing with complementary pyrimidine base which is thymine.
In guanine, nitrogen present at first position and amino group at second carbon along with oxo group at sixth carbon is involved in Watson-Crick base pairing with complementary pyrimidine base which is cytosine.
Thus, the positions of purine ring that have the property to form hydrogen bonds but do not participate in Watson-Crick base pairing are the nitrogen which is present at third and seventh position of purine ring.
Conclusion:
Third and seventh positions in purine ring are involved in hydrogen bonding but do not involve in Watson-Crick base pairing.
Want to see more full solutions like this?
Chapter 8 Solutions
Lehninger Principles of Biochemistry (Instructor's)
- To map the active site of -lactamase, the enzyme was hydrolyzed with trypsin to yield a hexapeptide (P1) with the following amino acids. Glu, Lys, Leu, Phe, Met, and Ser. Treatment of P1 with phenyl isothiocyanate yielded a PTH derivative of phenylalanine and a peptide (P2). Treatment of P1 with cyanogenbromide gave an acidic tetrapeptide (P3) and a dipeptide (P4).Treatment of P2 with 1-fluoro-2,4-dinitrobenzene, followed by complete hydrolysis, yields N-2,4-dinitrophenyl-Glu. P1, P2, and P3 contain the active site serine. Question: although S, K, and D are involved in the catalysis, the E in this hexapeptide does not participate in the hydrolysis of the b-lactam ring. Why is that?arrow_forwardTo map the active site of beta-lactamase, the enzyme was hydrolyzed with trypsin to yield a hexapeptide (P1) with the following amino acids. Glu, Lys, Leu, Phe, Met, and Ser. a) Using the experimental results described below deduce the primary sequence of the active site hexapeptide. Treatment of P1 with phenyl isothiocyanate yielded a PTH derivative of phenylalanine and a peptide (P2). Treatment of P1 with cyanogenbromide gave an acidic tetrapeptide (P3) and a dipeptide (P4).Treatment of P2 with 1-fluoro-2,4-dinitrobenzene, followed by complete hydrolysis, yields N-2,4-dinitrophenyl-Glu. P1, P2, and P3 contain the active site serine. please help!arrow_forwardThe beta-lactamase hydrolyzes the lactam-ring in penicillin. Describe the mechanism of hydrolysis, insuring to include the involvement of S, D, & K in the reaction sequence. Please helparrow_forward
- To map the active site of beta-lactamase, the enzyme was hydrolyzed with trypsin to yield a hexapeptide (P1) with the following amino acids. Glu, Lys, Leu, Phe, Met, and Ser. Treatment of P1 with phenyl isothiocyanate yielded a PTH derivative of phenylalanine and a peptide (P2). Treatment of P1 with cyanogenbromide gave an acidic tetrapeptide (P3) and a dipeptide (P4).Treatment of P2 with 1-fluoro-2,4-dinitrobenzene, followed by complete hydrolysis, yields N-2,4-dinitrophenyl-Glu. P1, P2, and P3 contain the active site serine. Why doesn't D in this hexapeptide not participate in the hydrolysis of the beta-lactam ring even though S, K, and D are involved in the catalyst?arrow_forwardTo map the active site of -lactamase, the enzyme was hydrolyzed with trypsin to yield a hexapeptide (P1) with the following amino acids. Glu, Lys, Leu, Phe, Met, and Ser. Treatment of P1 with phenyl isothiocyanate yielded a PTH derivative of phenylalanine and a peptide (P2). Treatment of P1 with cyanogenbromide gave an acidic tetrapeptide (P3) and a dipeptide (P4).Treatment of P2 with 1-fluoro-2,4-dinitrobenzene, followed by complete hydrolysis, yields N-2,4-dinitrophenyl-Glu. P1, P2, and P3 contain the active site serine. Using the experimental results described above derive the primary sequence of the active site hexapeptide. Please help!arrow_forwardWhich type of enzyme catalyses the following reaction? oxidoreductase, transferase, hydrolase, lyase, isomerase, or ligase.arrow_forward
- +NH+ CO₂ +P H₂N + ATP H₂N NH₂ +ADParrow_forwardWhich type of enzyme catalyses the following reaction? oxidoreductase, transferase, hydrolase, lyase, isomerase, or ligase.arrow_forwardWhich features of the curves in Figure 30-2 indicates that the enzyme is not consumed in the overall reaction? ES is lower in energy that E + S and EP is lower in energy than E + P. What does this tell you about the stability of ES versus E + S and EP versus E + P.arrow_forward
- BiochemistryBiochemistryISBN:9781319114671Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.Publisher:W. H. FreemanLehninger Principles of BiochemistryBiochemistryISBN:9781464126116Author:David L. Nelson, Michael M. CoxPublisher:W. H. FreemanFundamentals of Biochemistry: Life at the Molecul...BiochemistryISBN:9781118918401Author:Donald Voet, Judith G. Voet, Charlotte W. PrattPublisher:WILEY
- BiochemistryBiochemistryISBN:9781305961135Author:Mary K. Campbell, Shawn O. Farrell, Owen M. McDougalPublisher:Cengage LearningBiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage LearningFundamentals of General, Organic, and Biological ...BiochemistryISBN:9780134015187Author:John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. PetersonPublisher:PEARSON





