Scelta multipla
You perform multiple tests to derive the amino acid sequence of a purified peptide (see results below). Which of the following peptides listed best represents the sequence of the unknown peptide?
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5. Protein Techniques
Peptidases
Indietro5. Protein Techniques
Peptidases
- Scelta multiplaIn human gastrointestinal physiology, where does chemical protein digestion begin (i.e., where are proteins first enzymatically cleaved into peptides)?56views
- Scelta multiplaWhich enzyme class is primarily responsible for breaking down proteins into smaller peptides and amino acids?63views
- Scelta multiplaWhich enzyme is primarily responsible for breaking down proteins in the stomach?66views
- Domanda aperta
A) The octapeptide AVGWRVKS was digested with the enzyme trypsin. Would ion exchange or size-exclusion chromatography be most appropriate for separating the fragments? Explain.
a. Ion-Exchange chromatography.
b. Size-exclusion chromatography.
B) Suppose the same peptide was digested with chymotrypsin. Which would be the optimal separation technique? Explain.
a. Ion-Exchange chromatography.
b. Size-exclusion chromatography.
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Which is the expected result of chymotrypsin cleavage of the following peptide?
Lys—Gly—Phe—Thr—Tyr—Pro—Asn—Trp—Ser—Tyr—Phe
403views - Scelta multiplaIn human digestion, where does the digestion of protein begin?109views
- Scelta multiplaIn human digestion, where does protein digestion begin?65views
- Domanda aperta
The following reagents are often used in protein chemistry.Match the reagent with the purpose for which it is best suited.Some answers may be used more than once or not at all and more than one reagent may be suitable for a given purpose.
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Draw out each of the peptide fragments that would be generated if the peptide is treated with trypsin.
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What would the resulting peptide fragments be if the following peptide were treated with excess Pepsin?
H—E—L—P—M—E—P—L—E—A—S—E
301views - Domanda aperta
Draw out the resulting peptide fragments that would be generated if the peptide is treated with chymotrypsin.
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A nonapeptide was determined to have the following amino acid composition: (Lys)2, (Gly)2, (Phe)2, His, Thr, Met. The native peptide was incubated with 1-fluoro-2,4-dinitrobenzene (FDNB) and then hydrolyzed; 2,4-dinitrophenylhistidine was identified by HPLC. When the native peptide was exposed to cyanogen bromide (CNBr), an octapeptide and free glycine were recovered. Incubation of the native peptide with trypsin gave a pentapeptide, a tripeptide, and free Lys. 2,4-Dinitrophenyl-histidine was recovered from the pentapeptide, and 2,4-dinitrophenylphenylalanine was recovered from the tripeptide. Digestion with the enzyme pepsin produced a dipeptide, a tripeptide, and a tetrapeptide. The tetrapeptide was composed of (Lys)2, Phe, and Gly. The native sequence was determined to be:
*Recall: Pepsin cleaves N-terminal peptide bond of F, Y, W & L residues.*
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