Question

7. A polypeptide was subjected to the following treatments
with the indicated results. What is its primary structure?
I. Acid hydrolysis:
1. (Ala, Arg, Cys, Glx, Gly, Lys, Leu, Met: Phe, Thr)
II. Aminopeptidase M:
2. No fragments
III. Carboxypeptidase A + carboxypeptidase B:
3. No fragments
IV. Trypsin followed by Edman degradation of the separated
products:
4. Cys-Gly-Leu-Phe-Arg
5. Thr-Ala-Met-Glu-Lys​

Answer 1

Answer:

• Digestion of the native pig kidney fructose 1,6-bisphosphatase tetramer with subtilisin cleaves each of the 35,000-molecular-weight subunits to yield two major fragments: the S-subunit (Mr ca. 29,000), and the S-peptide (Mr 6,500). The following amino acid sequence has been determined for the S peptide: