Question

You are researching a cytoplasmic protein associated with a nerve disorder. The native form of the enzyme appears to be globular protein; however, when a sample of the purified protein is treated with a chemical that reduces disulfide bonds, the enzymatic activity decreases dramatically and multiple globular proteins can be detected in the sample. What does this tell you about the protein?a. The primary and secondary structure of the protein depends on disulfide bonds.

b. The protein is most likely composed of \alpha helices that are held together by disulfide bonds.
c. The protein is most likely composed of \betha sheets that are held together by disulfide bonds.
d. The primary structure of the protein contains multiple cysteine residues that are hydrolyzed by the chemical reductant.
e. The protein is most likely composed of multiple polypeptide chains that are held together by disulfide bonds.

Answer 1

The treatment of a cytoplasmic protein with a chemical that reduces disulfide bonds results in decreased enzymatic activity and the detection of multiple proteins, showing that the protein's quaternary structure is held together by disulfide bonds.

Step-by-step explanation:

Understanding the changes in enzymatic activity of a cytoplasmic protein associated with a nerve disorder when treated with a chemical reducing disulfide bonds is crucial for insights into the protein's structure. The observation that the enzyme activity decreases dramatically and multiple globular proteins can be detected after treatment indicates that the protein is likely composed of multiple polypeptide chains held together by disulfide bonds. These covalent bonds are essential for maintaining the protein's quaternary structure, which is critical for its proper function. The reduction of these bonds leads to the separation of the polypeptide chains and a consequent loss of activity, demonstrating the importance of the quaternary structure in the enzyme's functionality.

The observation that the enzymatic activity of a purified protein decreases dramatically and multiple globular proteins can be detected when a reducing agent is used to break disulfide bonds suggests that the protein's enzymatic activity depends on the presence of disulfide bonds. Disulfide bonds are covalent bonds between sulfur atoms in a polypeptide and play a role in stabilizing the protein's tertiary structure. Therefore, when the disulfide bonds are broken, the protein loses its native form and its enzymatic activity is affected.

Answer 2

e. The protein is most likely composed of multiple polypeptide chains that are held together by disulfide bonds.

Step-by-step explanation:

The disuplhide bond is formed between two thiol groups of cysteine residues in proteins. The disulphide linkages are found between secondary, tertiary and quaternary structure of protein.

Let us discuss the protein in example now;

The native form of the enzyme appears to be globular protein indicates that protein either have tertiary or quternary structure. Primary and secondary srtucture can't have globular protein.

when a sample of the purified protein is treated with a chemical that reduces disulfide bonds, the enzymatic activity decreases dramatically and multiple globular proteins can be detected in the sample indicates that proteins have Quaternary structure because quaternary structure comprises of more than one polypeptide chain and each polypeptide can exhibit globular structure.

That why we can say The protein is most likely composed of multiple polypeptide chains (quaternary structure) that are held together by disulfide bonds.