PsiD is the first enzyme on the mushroom’s psilocybin assembly line. A 2017 study from the Hans Knöll Institute in Jena characterized it as a new class of fungal L-tryptophan decarboxylase, one of four psilocybin enzymes alongside PsiK, PsiM and PsiH (Fricke et al., 2017). Together with PsiH, which adds a hydroxyl at the 4-position, it turns L-tryptophan into 4-hydroxytryptamine (Hudspeth et al., 2024).
The same paper showed that PsiD, PsiK and PsiM together could make psilocybin in a test tube from a form of tryptophan that already carried the oxygen at position 4 (Fricke et al., 2017). That three-enzyme route has since been used to study the pathway in bacteria (Adams et al., 2022).
PsiD is also a tool for tracing evolution. A 2024 genome study built a family tree of PsiD genes that placed Psilocybe alongside Panaeolus, Gymnopilus, Pluteus and Pholiotina (Bradshaw et al., 2024). Before that study the gene cluster had been described in only five of about 165 Psilocybe species, so the tree is far from complete.
Sources
- Fricke et al., 2017, Angewandte Chemie
- Hudspeth et al., 2024, Nature Communications
- Bradshaw et al., 2024, PNAS
- Adams et al., 2022, Metabolic Engineering Communications
Last checked .