Question

Yassmeen is a starting Biochemist. A sequence is required. The information that Yassmeen has is as follows: A.) The Peptide is composed of 18 Amino Acids. They are: [A-1; C-2; D-1; F-2; G-2; K-1; L-1; N-2; S-1; T-1; V-1; Y-1; W-1]. B.) Treatment of the Peptide DNFB gave the following adducts: --8-0-y -N-C-C-oH I H Nar C.) Treatment of the intact peptide with Carboxypeptidase "C" gave. "N" D.) Treatment of the intact Peptide with "Elastase" gave the following: 1.) T-A; F-G; S-C-C-V; F-K-N; W-D-N; L-K-Y-G: E.) Treatment of the intact peptide with DTT (Dithiothreitol), and subsequent treatment of the resultant peptide with "Thermolysine" gave the following: 1.) T-A-C; F-K-N; F-G-C-S; V-L-K; Y-G; W-D-N Show Yassmeen that You are good at sequencing and determine the Primary Structure of this peptide.

Answer 1

Elastace cleavage site is at c terminal of Ala, val, ser Gly, new, Ile. DDT cleares disulphide bond Themolysine cleares ofter at the N-terminal of hydrophobic amino acids like Ile, that, the, Top, Tag, Tyr val and from the data we know that DNFB showed that in the N-terminal there are 2 amino acids ie Prearyl alanine & Threonine. This dearly states that two chain are present joined by disulphide bond. An c) from this data we know that there is Nie. Arginine present in both the c terminal of the peptide since only Arginine is there therefore both peptice have Arginine in C terminal. Therefore the peptice is like. N- Phe Arg - C terminal N Thr - Arg - Creunited 1 Elastace Treatment releved, revealed. Thre-Ala , Phe-aly, ser-Gly-Gly-val, the-lys-Arg, Top-Asp - Arg, Leo-lys- Tyr-Gly

After elastace treatment. 't-means clearage site. Since after cleavage we cannot say which in N-term and which is Germinal so both side can be used. phobic The Alaf , Phe-clyf, tsen-lys-lys-valf Phe-lys- Arg , Trp- Asp - Aug 1 And after DOT & Thermolysine Thr-Ala-lyst , tene-lys-Arg , fene-City-Cys- ser, tral-leo-lys, Top-Asp-Ang , flyr - Gly So from this data after comparing we know that & Thr-Ala-Cys is common. So we can says 1) Thr-Ala that The-Ala-Cys- - Phe Is the peptide

2 in case of DDT and Themo Cyrine treatment we know that it cleares after disulphidle bonds & Noten of the so we can say. The - Ala - Cys The-Gly-Cys - ser – Ang 3) We can also see that in elastace that there must be a valive as it has a Sen-Cys lgs- Val. After Cys fragment . Thre - Ala - Cys - Val - Ang -n- The-Glycys - ser 4) In case of DDT & Theronolyrine we saw that val is followed by Leo & lys. Co- The- Ale - Cys - Val - Lew-lys - The Gly-cys-sen -

5) We can also see in Elastace that after Lev-Lysages nor Tyr & Aly must be there as it has a fragment of Lew-Lys - Tyr-Gly Thr-Ala-Cys-val - Leo-lys - Tyr-Gly Ang s n- the - alg–Cys - ser thence the polypeptide is (N) The- Ala - cys - Val - Lev-lys - Tyr-Gly- Phe-lys-Arg (c- temi cr-in- (N) Phe-Cily - cys - sen - Top - Asp - Arg (eterminal)