Question

anyone can help me with it?

A protein biochemist attempted to determine the amino acid sequence of a decapeptide. Use the results from the trypsin, chymotrypsin, and cyanogen bromide treatments to suggest the amino acid sequence of this decapeptide. Trypsin digestion gave two fragments with multiple residues (not in order): • T1: Ala, Arg, Phe, Gly, Thr, Trp, Tyr • T2: Lys, Met, Val Chymotrypsin digestion gave four fragments with multiple residues (not in order): • CT1: Ala, Phe • CT2: Thr, Trp • CT3: Lys, Met, Tyr, Val • CT4: Arg, Gly Treatment with cyanogen bromide yielded a single amino acid, methionine, and a nonapeptide. What is a possible sequence of the decapeptide? Use three-letter abbreviations in your answer, and add a dash between each residue. sequence:

Answer 1

Answer:

• The decapeptide is Met-Val-Lys-tyr-thr-trp-ala-arg-pro-phe

1):

• carbonyl side of Met (met and nonapeptide)

2):

• Trypsin cleaves on the C side of Lys and Arg but not on the N side of Pro.
• Thismeans that Lys is the last aminoacid in T2 (only trypsin fragment containing Met)
• $\rightarrow$Hence, Met-Val-lys-........

3):

• The middle portion of the sequence can be determined from the chymotrypsin digestion.
• Chymotrypsin cleaves on the C side of phe, trp, tyr but not on the N side of pro.

4):

• CT3 has Lys, met, tyr, val. Since met-val and tyr are first 3 aminoacids so tyr must be in 4th. This gives Met-Val-Lys-Tyr-....

5):

• CT1 has ala, arg, phe, pro, since CT cleaves C side of phe the last aminoacid should be Phe.
• Also CT1 has first aminoacid as ala. Moreover trypsin doesnot cleaves on the N side of pro.
• so the sequence of CT1 stands: ala-arg-pro-phe.

6):

• In CT2 chymotrypsin cleavages on the C side of trp. So the sequence of CT2 stands as thr-trp and is present in the middle.
• Therefore the whole sequence of decapeptide stands as:

$\rightarrow$Met-Val-Lys-tyr-thr-trp-ala-arg-pro-phe

Please Rate My Answer..... Thank.....u...