Chapter 5, Problem 28CQ

(a)

Summary Introduction

To determine: The maximum number of peptides when the polypeptide is cleaved with cyanogen bromide.

Concept introduction: Proteins are made up of one or more amino acids linked together to form a chain. The building blocks of the protein is called amino acid. Amino acids are termed as residues if they release a hydrogen ion from the amine end or a hydroxyl ion from the carboxyl end, or both; a water molecule is released as a result of formation of each amide bond. When more than eight peptides are linked together by peptide bonds, it forms a polypeptide.

Given: The given polypeptide sequence is as follows:

1 Ala   4 Arg   2 Asn   3 Asp   4 Cys   3 Gly   1 Gln   4 Glu

1 His   1 Lys   1 Met   1 Phe   2 Pro   4 Ser   2 Tyr   1 Trp

(b)

Summary Introduction

To determine: The maximum number of peptides when the polypeptide is cleaved with chymotrypsin.

Concept introduction: Proteins are made up of one or more amino acids linked together to form a chain. The building blocks of the protein is called amino acid. Amino acids are termed as residues if they release a hydrogen ion from the amine end or a hydroxyl ion from the carboxyl end, or both; a water molecule is released as a result of formation of each amide bond. When more than eight peptides are linked together by peptide bonds, it forms a polypeptide.

Given: The given polypeptide sequence is

1 Ala   4 Arg   2 Asn   3 Asp   4 Cys   3 Gly   1 Gln   4 Glu

1 His   1 Lys   1 Met   1 Phe   2 Pro   4 Ser   2 Tyr   1 Trp

(c)

Summary Introduction

To determine: The maximum number of disulfide bonds that can be formed.

Concept introduction: Proteins are made up of one or more amino acids linked together to form a chain. Amino acids are the building blocks of the protein. When more than eight peptides are linked together by peptide bonds, it forms a polypeptide. Disulfide bonds play a vital role in folding and maintaining the stability of proteins.

Given: The given polypeptide sequence is as follows:

1 Ala   4 Arg   2 Asn   3 Asp   4 Cys   3 Gly   1 Gln   4 Glu

1 His   1 Lys   1 Met   1 Phe   2 Pro   4 Ser   2 Tyr   1 Trp

(d)

Summary Introduction

To determine: The number of different arrangements of disulfide bonds that are possible in the given polypeptide sequence.

Concept introduction: Proteins are made up of one or more amino acids linked together to form a chain. Amino acids are the building blocks of the protein. When more than eight peptides are linked together by peptide bonds, it forms a polypeptide. Disulfide bonds play a vital role in folding and maintaining the stability of proteins.

Given: The given polypeptide sequence is as follows:

1 Ala   4 Arg   2 Asn   3 Asp   4 Cys   3 Gly   1 Gln   4 Glu

1 His   1 Lys   1 Met   1 Phe   2 Pro   4 Ser   2 Tyr   1 Trp