Question

A decapeptide that is part of an insulin-like peptide has the molecular formula: Asn, Arg(2), Ser(3), Phe, Cys, Leu, Thr. After partial hydrolysis, the fragments are: Cys-Ser-Phe-Ser- Arg-Asn-Ser-Cys Thr-Leu-Arg Ser-Thr What is the sequence? Ser-Phe-Ser-Thr-Leu-Arg-Arg-Asn-Ser-Cys Arg-Asn-Ser-Cys-Ser-Phe-Ser-Thr-Leu-Arg Ser-Thr-Arg-Asn-Ser-Cys-Ser-Phe-Ser- Asn Thr-Leu-Arg-Asn-Ser-Cys-Ser-Phe-Ser-Phe

Answer 1

Q1 - all the fragments can be found in the given sequence in option no 2. Further, option 3 and 4 can be eliminated coz it's given in question that, the sequence should contain, 2Arg molecules, and option 3 and 4 doesn't have that. So we are left with option 1 and 2. Out of these, the fragments, after partial hydrolysis, can be found in option no. 2 sequence. The order is also same. Hence 2ND OPTION is the CORRECT one.

Q2. Number of NMR signals are 5. The question can be solved by just counting the no. Of signals in all the molecules. Option 1 has 5 signals. Option 2 has 6 signals. Option 3 has 4 signals. And option 4 has 3 signals only. Hence the CORRECT option is OPTION NO 1.