1398507-94-2

Upstream product

• 73-22-3 L-Tryptophan 
• 153-94-6 D-tryptophan 
• 2380-86-1 6-hydroxy-1H-indole 
• 56-45-1 L-serin 

Downstream Products

• 179669-87-5 N-Boc-6-hydroxy-L-tryptophan 

Relevant academic research and scientific papers

SYNTHESIS OF (S)-6-HYDROXYTRYPTOPHAN AND DERIVATIVES THEREOF

The present invention relates to novel methods and compounds for synthesizing amanitin derivatives. The invention in particular relates to methods for synthesizing (S)-6-hydroxy-tryptophan derivatives which can be used as building blocks for synthesizing

Isolation of 6-hydroxy-L-tryptophan from the fruiting body of Lyophyllum decastes for use as a tyrosinase inhibitor

Tyrosinase is the key enzyme that controls melanin formation. We found that a hot water extract of the lyophilized fruiting body of the fungus Lyophyllum decastes inhibited tyrosinase from Agaricus bisporus. The extract was fractionated by ODS column chromatography, and an active compound was obtained by purification through successive preparative HPLC using an ODS and a HILIC column. Using spectroscopic data, the compound was identified to be an uncommon amino acid, 6-hydroxytryptophan. 6-Hydroxy-L-tryptophan and 6-hydroxy-D-tryptophan were prepared through a Fenton reaction from L-tryptophan and D-tryptophan, respectively. The active compound was determined to be 6-hydroxy-L-tryptophan by comparison of their circular dichroism spectra and retention time on HPLC analysis of the Nα-(5-fluoro-2,4-dinitrophenyl)-L-leuciamide derivative with those of 6-hydroxy-L-tryptophan and 6-hydroxy-D-tryptophan. A Lineweaver-Burk plot of the enzyme reaction in the presence of 6-hydroxy-L-tryptophan indicated that this compound was a competitive inhibitor. The IC50 values of 6-hydroxy-L-tryptophan was 0.23 mM.

Directed evolution of the tryptophan synthase β-subunit for stand-alone function recapitulates allosteric activation

Enzymes in heteromeric, allosterically regulated complexes catalyze a rich array of chemical reactions. Separating the subunits of such complexes, however, often severely attenuates their catalytic activities, because they can no longer be activated by their protein partners. We used directed evolution to explore allosteric regulation as a source of latent catalytic potential using the β-subunit of tryptophan synthase from Pyrococcus furiosus (PfTrpB). As part of its native αββα complex, TrpB efficiently produces tryptophan and tryptophan analogs; activity drops considerably when it is used as a stand-alone catalyst without the α-subunit. Kinetic, spectroscopic, and X-ray crystallographic data show that this lost activity can be recovered by mutations that reproduce the effects of complexation with the α-subunit. The engineered PfTrpB is a powerful platform for production of Trp analogs and for further directed evolution to expand substrate and reaction scope.

Synthesis and biological evaluation of 18F-labeled fluoroethoxy tryptophan analogues as potential PET tumor imaging agents

As a continuation of our research efforts toward the development of tryptophan-based radiotracers for tumor imaging with positron emission tomography (PET), three new fluoroethoxy tryptophan analogues were synthesized and evaluated in vivo. These new tracers (namely, 4-(2-[18F]fluoroethoxy)-DL-tryptophan ([18F]4-FEHTP), 6-(2-[18F]fluoroethoxy)-DL-tryptophan ([18F]6-FEHTP), and 7-(2-[18F]fluoroethoxy)-DL-tryptophan ([18F]7-FEHTP) carry the fluoroethoxy side chain either at positions 4-, 6-, or 7- of the indole core. Reference compounds and precursors were synthesized by multistep approaches. Radiosynthesis was accomplished by no-carrier-added nucleophilic 18F-fluorination following either an indirect approach (O-alkylation of the corresponding hydroxytryptophan with [18F]fluoroethyltosylate) or a direct approach (nucleophilic [18F] fluorination using a protected mesyl precursor). Radiochemical yields (decay corrected) for both methods were in the range of 10-18%. Small animal PET imaging with xenograft-bearing mice revealed the highest tumor/background ratio for [18F]6-FEHTP which, in a direct comparison, outperformed the other two tryptophan tracers and also the well-established tyrosine analogue O-(2-[18F]fluoroethyl)-L-tyrosine ([18F]L-FET). Investigation of the transport mechanism of [18F]6-FEHTP in small cell lung cancer cells (NCI-H69) revealed that it is most probably taken up exclusively via the large neutral amino acid transporter(s) (LAT).