Concept explainers
(a)
To determine: The overall reaction of dextran
Introduction:
Dental caries is a most prevalent infection in humans. This disease is characterized by the tooth breakdown due to acid ferment by acidifying bacteria. The bacteria inside tooth ferment synthesized the water insoluble network of dextran. This dextran is also called as dental plaques which are composed of
(b)
To determine: The way in which dietary sucrose also provide oral bacteria with an abundant source of
Introduction:
Dental caries is a most prevalent infection in humans. This disease is characterized by the tooth breakdown due to acid ferment by acidifying bacteria. The bacteria inside tooth ferment synthesized the water insoluble network of dextran. This dextran is also called as dental plaques which are composed of

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Chapter 20 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: the b-lactamase hydrolyzes the lactam-ring in antibiotics like penicillin. Describe the mechanism, of hydrolysis, insuring to include the involvement of S, D, and K in the reaction sequence. Please help!arrow_forwardThree of these amino acids participate in the proteolytic hydrolysis of polypeptides. Show the charge-relay network generated by the serine proteases and identify the nucleophilic species that initiates the hydrolysis. please help!arrow_forwardYou have isolated a protein and determined that the native molecular weight of the holoenzyme is 160 kD using size exclusion chromatography. Analysis of this protein using SDS-PAGE revealed 2 bands, one at 100 kD and one at 30 kD. 1. Describe the architecture of the polypeptide component of this enzyme. 2. The enzyme was found to be 0.829% NAD (by weight). What further can be said regarding the architecture? can you please help me with question number 2arrow_forward
- 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
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