Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2023 Jun 1;14(3):858–878. doi: 10.14336/AD.2022.0916

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright: © 2023 Huang et al.

this is an open access article distributed under the terms of the creative commons attribution license, which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed.

PMC Copyright notice

Figure 1. — Tryptophan metabolism by the kynurenine and methoxyindole pathways. Kynurenine is a central KP metabolite capable of degradation through three specific pathways, shown in (1), (2) and (3) in the schematic diagram, to generate different neuroactive metabolites. Abbreviations: TRP, tryptophan; IDO, indoleamine-2,3-dioxygenase; TDO, tryptophan-2,3-dioxygenase; KAT, kynurenine aminotransferase I-III; AA, anthranilic acid; 3-HK, 3-hydroxykynurenine; 3-HAA, 3-hydroxyanthrenillc acid; KMO, kynurenine 3-monooxygenase; HAAO, 3-hydroxyanthranilate 3,4-dioxygenase; KP, kynurenine pathway; KYNA, kynurenic acid; PA, picolinic acid; QUINA, quinolinic acid; TPH, tryptophan hydroxylase; CA, cinnabarinic acid; XA, xanthurenic acid; NAD⁺, nicotinamide adenine dinucleotide; 5-HT, 5-hydroxytryptophan; TPH, tryptophan hydroxylase.