Question

#3. Under experimental conditions, you purify a known, biologically important peptide from human tissue. To determine the overall sequence, you then digest the pure peptide with trypsin and chymotrypsin (each separately) and then use mass spectrometry to identify the following sequence fragments from the overall peptide (shown in order of relative length, not necessarily in the order in which they are assembled in the whole, natural peptide). Trypsin cleavage products: Chymotrypsin cleavage products: K, GE, NAYK, NAIIK, SQTPLVTLFK, YGGFMTSEK Y, GGF, KNATIKNAYKKGE, MTSEKSOTPLVTLF In a separate experiment, one round of Edman degradation of the whole peptide, via treatment with phenylisothiocyaniate (PTC), reveals that the amino terminus residue is a tyrosine. Taken together, use your knowledge of trypsin and chymotrypsin sequence cleavage site specificity to reassemble the overall peptide sequence that includes each of the fragments in the correct order. Once you believe you know the correct answer, enter your sequence into the "NCBI protein blast" tool and report the top hit below. Be careful though, a partial sequence is likely to produce the wrong answer! Whole peptide sequence: Peptide name and organism it belongs to): #4. Based on your answer from question #3, DRAW the N-terminal peptide product that you would get (also the shorter of the 2) if you were to digest the whole peptide from problem #3 with the chemical, cyanogen bromide. Include the correct stereochemistry, sidechains, all non- aromatic hydrogens, and charges at pH 7.4 for the peptide product drawn below.

Please explain each part !! Thank you !!

Answer 1

Question 3

A) whole peptide sequence:

(N terminal ) YGG FMT SEK SQT PLV TLF KNA IIK NAY KKG E (C terminal)

B) protein name is endorphin beta ( homo spiens)

Please post each question separate according to the guidelines