IFN- \(\alpha\) administration induces the degradation of the amino acid: a. choline b. cysteine c. serine d. tryptophan e. tyrosine

Interferon-alpha (IFN-α) is an antiviral cytokine, a type of protein involved in the immune response. It plays a role in modulating the immune system, which can, in turn, affect the degradation of certain amino acids.

Let's look at each amino acid and determine if it is likely to be degraded upon IFN-α administration: a. Choline - Although important in cell membrane function, choline is not an amino acid and thus can be eliminated from the list. b. Cysteine - It is an amino acid critical for the synthesis of proteins and the maintenance of certain cellular structures, but it is not directly linked to the response of IFN-α in the immune system. c. Serine - Serine is a non-essential amino acid that plays a role in metabolism and various cellular functions. However, its degradation is not linked to the immune response and thus not linked to IFN-α administration. d. Tryptophan - Tryptophan is an essential amino acid known for its role in the production of serotonin, which affects mood and sleep. It has been found that IFN-α administration induces the enzyme indoleamine 2,3-dioxygenase (IDO) responsible for tryptophan degradation as a part of the antiviral defense mechanism. e. Tyrosine - Tyrosine is an amino acid precursor to various neurotransmitters and hormones, but its degradation is not directly influenced by the presence of IFN-α.

Given the analysis in step 2, we can conclude that tryptophan (d) is the amino acid that is degraded upon IFN-α administration. The response of IDO induction upon IFN-α administration is directly related to tryptophan degradation as a part of the immune system's antiviral defense mechanism.