cDNAs encoding the full-length sequence for tryptophan hydroxylase, and deletion mutants consisting of the regulatory (amino acids 1-98) or catalytic (amino acids 99-444) domains of the enzyme, were cloned and expressed as glutathione S-transferase fusion proteins in E. coli. The recombinant fusion proteins could be purified to near homogeneity within minutes by affinity chromatography on glutathione-agarose. The full-length enzyme and the catalytic core expressed very high levels of tryptophan hydroxylase activity. The regulatory domain was devoid of activity. The full-length enzyme and the catalytic core, while adsorbed to glutathione-agarose beads, obeyed Michaelis-Menten kinetics, and the kinetic properties of each recombinant enzyme for cofactor and substrate compared very closely to native, brain tryptophan hydroxylase. Both active forms of the glutathione S-transferase-tryptophan hydroxylase fusion proteins had strict requirements for ferrous iron in catalysis and expressed much higher levels of activity (Vmax) than the brain enzyme. Analysis of full-length tryptophan hydroxylase and the catalytic core by molecular sieve chromatography under nondenaturing conditions revealed that each fusion protein behaved as a tetrameric species. These results indicate that a truncated tryptophan hydroxylase, consisting of amino acids 99-444 of the full-length enzyme, contains the sequence motifs needed for subunit assembly. Both wild-type tryptophan hydroxylase and the catalytic core are expressed as apoenzymes which are converted to holoenzymes by exogenous iron. The tryptophan hydroxylase catalytic core is also as active as the full-length enzyme, suggesting the possibility that the regulatory domain exerts a suppressive effect on the catalytic core of tryptophan hydroxylase.
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http://dx.doi.org/10.1046/j.1471-4159.1996.67030917.x | DOI Listing |
Vet Parasitol
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College of Veterinary Medicine, Jilin Agricultural University, Changchun 130118, China; Jilin Provincial Engineering Research Center of Animal Probiotics, Jilin Provincial Key Laboratory of Animal Microecology and Healthy Breeding, Jilin Agricultural University, Changchun 130118, China; Engineering Research Center of Microecological Vaccines (Drugs) for Major Animal Diseases, Ministry of Education, Jilin Agricultural University, Changchun 130118, China. Electronic address:
During the intestinal stage of Trichinella spiralis (T. spiralis) infection, it can stimulate host's intestinal peristalsis to expulse worms. 5-hydroxytryptamine (5-HT) is a neurotransmitter which can regulate the contraction of intestinal smooth muscle.
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Department of Traditional Chinese Medicine, Nanjing Drum Tower Hospital Clinical College of Nanjing University of Chinese Medicine, Nanjing, China; Department of Traditional Chinese Medicine, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China. Electronic address:
Depression is commonly associated with gastrointestinal (GI) disorders, such as constipation, which can potentially intensify depressive symptoms. The interplay between these conditions is believed to be facilitated by the gut-brain axis, which suggests a complex bidirectional interaction. Current treatments, such as antidepressants and prokinetics, are often associated with side effects and high recurrence rates, highlighting the need for effective treatments targeting both depression and constipation.
View Article and Find Full Text PDFComp Biochem Physiol C Toxicol Pharmacol
January 2025
College of Fisheries, Henan Normal University, Xinxiang 453007, PR China; Engineering Technology Research Center of Henan Province for Aquatic Animal Cultivation, Henan Normal University, Xinxiang 453007, PR China. Electronic address:
Olanzapine (OLZ) is widely used in the treatment of schizophrenia, and its metabolic side effects have garnered significant attention in recent years. Despite this, the specific side effects of OLZ and the underlying mechanisms remain inadequately understood. To address this gap, zebrafish (Danio rerio) were exposed to OLZ at concentrations of 35.
View Article and Find Full Text PDFGut Microbes
December 2025
MOE/NHC/CAMS Key Lab of Medical Molecular Virology, School of Basic Medical Sciences, & National Clinical Research Center for Aging and Medicine, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China.
The gut microbiota plays a pivotal role in anxiety regulation through pathways involving neurotransmitter production, immune signaling, and metabolic interactions. Among these, gut-derived serotonin (5-hydroxytryptamine, 5-HT), synthesized from tryptophan metabolism, has been identified as a key mediator. However, it remains unclear whether specific microbial factors regulate tryptophan metabolism to influence 5-HT production and anxiety regulation.
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State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, China; School of Food Science and Technology, Jiangnan University, Wuxi, China; National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, China; (Yangzhou) Institute of Food Biotechnology, Jiangnan University, Yangzhou, China. Electronic address:
This study was conducted to elucidate the effects of different degrees of substitution (DS) on the properties of propionylated and butyrylated starches and to investigate their efficacy and mechanisms in ameliorating autism-like phenotypes. Fourier transform infrared spectra of propionylated and butyrylated starches revealed the presence of the CO absorption peak at 1730 cm. Additionally, as the DS increased, the surface of the starch granules became rougher, and the crystallinity decreased.
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