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A nonapeptide was determined to have the following amino acid composition: (Lys)2, (Gly) 2, (Phe) 2, His, Leu, 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. What is the native sequence of the peptide?

User PIKP
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Answer:

His-Leu-Phe-Gly-Lys-Lys-Phe-Met-Gly

Step-by-step explanation:

An amino acid is an organic compound that contains a carboxylic group and amino groups. The amino acid is commonly used as a building block for a typical protein. There are different amino acid compositions in a given protein. The amino acid composition of the nonapeptide given in the problem is shown above.

User Jochen Walter
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