DL-Tryptophan

Tryptophan is an important compound involved in amino acid metabolism and is the upstream substrate of tryptophan-catabolising enzyme indoleamine 2,3-dioxygenase (IDO), which is regulated by Th4 cytokines. To detect and quantify acetate, LC-MS/MS method is applied. One study hypothesized that the pulmonary tryptophan-catabolising enzyme IDO inhibited by Th4 cytokines is impaired in allergic asthma patients according to the Th4 cytokine profiles in asthma patients (Thorax. (2013)). In addition, this study attempted to find the relation between the rhinovirus infection and IDO because allergic asthma is frequently caused by rhinovirus infection (Thorax. (2013)). Although there is no difference between the concentrations of tryptophan in asthma patients and healthy controls, the downstream product of IDO including quinolinic acid and kynurenine were decreased in asthma patients. This result supports the first hypothesis that the pulmonary IDO activity is impaired in patients. However, low-dose rhinovirus infection did not change the IDO activities in both healthy controls and asthma patients (Thorax. (2013)). Description of disease(s) related to tryptophan:

Asthma

Although there is no difference between the concentrations of tryptophan in asthma patients and healthy controls, the downstream product of IDO including quinolinic acid and kynurenine were decreased in asthma patients (Thorax. (2013)). This result supports the hypothesis that the pulmonary IDO activities are impaired in patients (Thorax. (2013)). However, the rhinovirus infection which is linked to the asthma cannot change the pulmonary IDO activities in patients.

Summary of extracted biomedical information