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PubMed1981

Tryptophan malabsorption in dementia. Improvement in certain cases after tryptophan therapy as indicated by mental behaviour and blood analysis.

Twenty-four senile dementia patients in the age range 65-85 years were subjected to a new sensitive tryptophan loading test: Dopa-Tryptophan loading ("Dop-Try loading") in order to determine whether Try malabsorption occurs in senile dementia and if so how frequent this is. For comparison the same loading test was performed on 23 subjects in the same age grouping but with normal metal function. The differences in Try absorption were statistically analyzed and this revealed that absorption was less effective in the senile dementia group. Four patients with Try malabsorption were treated with 3 G 1-Try + 50 Mg dl-5-hydroxytryptophan (5-HTP) per day orally for 20-30 days and four patients with normal absorption were treated in the same way. The Dop-Try loading test was repeated after this treatment. Two patients showed improved absorption and coincident mental improvement, while one showed decreased absorption and mental deterioration. One died during the course of the treatment. None of the four patients with normal absorption showed mental improvement after the treatment. This pilot study suggests that increase in Try absorption following the Try treatment is a necessary condition for improvement in the mental state. The study is being continued with larger numbers of patients.

5-Hydroxytryptophan↗
PubMed1997

Comparison of the adsorption ability between tryptophan and modified tryptophan columns.

Immunoadsorption therapy (IAT) using the tryptophan column (TR:TR-350, Asahi Medical Co., Tokyo, Japan) is used for patients with Guillain-Barré syndrome or Fisher's syndrome. Recently, a modified tryptophan column (modified TR:TR-350S, Asahi) was developed to reduce adsorption of fibrinogens. However, it is not clear whether the new column can effectively adsorb the antiganglioside antibodies. We treated 2 patients with Guillain-Barré syndrome, 1 patient with Fisher's syndrome, and 1 patient with Bickerstaff's brainstem encephalitis by IAT using the TR and the modified TR. Samples were taken from the inlet and outlet of the affinity column. We compared the adsorption ability of antiganglioside antibodies between the TR and modified TR. The modified TR adsorbed antiganglioside antibodies less effectively than the TR. No significant bleeding was observed in the patients during each session. Furthermore, results of the clinical study were confirmed by batchwise adsorption test. We propose that the modified TR should not be used for treating patients with Guillain-Barré syndrome and related disorders.

Adsorption↗
PubMed2000

A Bacillus subtilis gene of previously unknown function, yhaG, is translationally regulated by tryptophan-activated TRAP and appears to be involved in tryptophan transport.

Computer analysis of the Bacillus subtilis genome sequence revealed a gene with no previously attributed function, yhaG, specifying a transcript containing a presumptive binding site for the tryptophan-activated regulatory protein, TRAP. The presumptive TRAP binding site overlaps the yhaG Shine-Dalgarno sequence and translation initiation region. TRAP was shown to regulate expression of yhaG translationally. Production of the yhaG transcript in vivo was found to compete for the binding of TRAP to other known TRAP binding sites. YhaG is likely to be a transmembrane protein involved in tryptophan transport.

Amino Acid Sequence↗
PubMed1993

Pathological and immunological effects of ingesting L-tryptophan and 1,1'-ethylidenebis (L-tryptophan) in Lewis rats.

The eosinophilia-myalgia syndrome (EMS) has been associated with ingestion of L-tryptophan (L-TRP) produced by a single manufacturer. Epidemiological data implicated 1,1'-ethylidenebis (L-tryptophan) (EBT) (peak 97 or peak E) as a possible etiologic agent. We showed previously that Lewis rats treated with the L-TRP implicated in EMS develop fasciitis and perimyositis similar to those seen in human EMS. We now report the pathology associated with the treatment of Lewis rats with synthetic EBT and/or L-TRP. All animals treated for 6 wk with case-associated L-TRP or EBT developed significant myofascial thickening, compared with animals in the vehicle control and control L-TRP groups. However, even those animals receiving the control L-TRP showed a mild but significant increase in the thickness of the myofascia, compared with vehicle-treated control animals. All animals except vehicle controls also exhibited significant pancreatic pathology, including fibrosis and acinar changes. Only animals treated with case-associated L-TRP for 6 wk showed evidence of immune activation with increased frequency of CD8, Ia, and IL-2 receptor-positive cells in the peripheral blood. Animals receiving L-TRP or EBT for < 6 wk did not show significant differences in myofascial thickness, although these animals did show pancreatic acinar changes. Although these results demonstrate for the first time the pathological effects of EBT, they do not rule out the possibility that other impurities in the EMS-case-associated L-TRP may also contribute to some of the features of EMS.

Animals↗
PubMed2002

Cerebrospinal fluid glutamine, tryptophan, and tryptophan metabolite concentrations in dogs with portosystemic shunts.

OBJECTIVE: To determine whether glutamine (GLN), tryptophan (TRP), and tryptophan metabolite concentrations are higher in cerebralspinal fluid (CSF) dogs with naturally occurring portosystemic shunts (PSS), compared with control dogs. ANIMALS: 11 dogs with confirmed PSS and 12 control dogs fed low- and high-protein diets. PROCEDURE: Cerebrospinal fluid and blood samples were collected from all dogs. Serum and CSF concentrations of GLN, alanine, serine, TRP, 5-hydroxyindoleacetic acid (5-HIAA), and quinolinic acid (QUIN) were measured. RESULTS: Cerebrospinal fluid concentrations of GLN, TRP, and 5-HIAA were significantly higher in PSS dogs, compared with control dogs fed high- or low-protein diets. Cerebrospinal fluid QUIN concentration was significantly higher in PSS dogs, compared with control dogs fed the low-protein diet. Serum QUIN concentration was significantly lower in PSS dogs, compared with control dogs fed either high- or low-protein diets. CONCLUSIONS AND CLINICAL RELEVANCE: An increase in CNS GLN concentration is associated with high CSF concentrations of TRP and TRP metabolites in dogs with PSS. High CSF 5-HIAA concentrations indicate an increased flux of TRP through the CNS serotonin metabolic pathway, whereas high CSF QUIN concentrations indicate an increased metabolism of TRP through the indolamine-2,3-dioxygenase pathway. The high CSF QUIN concentrations in the face of low serum QUIN concentrations in dogs with PSS indicates that QUIN production from TRP is occurring in the CNS. High concentrations of QUIN and other TRP metabolites in the CNS may contribute to neurologic abnormalities found in dogs with PSS and hepatic encephalopathy.

Alanine↗
PubMed1997

Marginal efficiency of free or protected crystalline L-tryptophan for tryptophan and protein accretion in early-weaned pigs.

We conducted an experiment to determine the efficiency of dietary tryptophan (Trp) for protein and Trp accretion in 4-kg (live weight) pigs. Five Trp-deficient diets were fed for 18 d after weaning. The basal diet contained 23.4% protein and .14% Trp. The four other diets were similar to the basal diet but were supplemented with .06 or .12% free or protected crystalline Trp. No differences were found between the two crystalline Trp forms for all variables under study. Equal amounts of all diets were fed by intragastric tube feeding. Daily weight gain (P < .10), gain:feed (P < .05), and daily protein retention (P < .01) increased linearly as dietary Trp increased. Similarly, retention and gross efficiency (retained: intake) of almost all amino acids increased. Tryptophan retention also increased linearly (P < .05), but gross efficiency was maximal (40.1%) with protein-bound Trp from the basal diet, and it decreased linearly as dietary Trp increased. This important reduction was the result of a low marginal efficiency for crystalline (13.6 +/- 3.3%) free or protected Trp.

Aging↗
PubMed1980

Time-course of changes of liver tryptophan pyrrolase (tryptophan oxygenase) and liver and kidney glucose-6-phosphatase in rats shifted from high- to zero-protein diets.

Time-courses of changes in the activities of liver and kidney glucose-6-phosphatase [EC 3.1.3.9] and hepatic tryptophan pyrrolase [EC 1.13.1.12; TPO] in rats pre-fed high-protein diets for 5 days and then shifted to zero-protein diets were studied. Liver glucose-6-phosphatase activity decreased 1 day after the dietary shift but then increased and remained significantly higher than the 0 day value for the next 2 days. Changes in liver glycogen were found to be intimately and inversely related to liver glucose-6-phosphatase activity. Changes in kidney glucose-6-phosphatase activity paralleled the pattern of changes observed in liver activity. An initial decrease in TPO activity was followed by increased enzyme activity up to the 3rd day of the dietary shift. Later there was a rapid fall in tryptophan pyrrolase activity. Changes observed in these specific enzyme proteins differed from those observed in total tissue proteins. Alterations in the activities of these enzymes and changes in other parameters are compared with those observed earlier with the reverse type of dietary shift.

Animals↗
PubMed1992

Amino acid substitutions at tryptophan 388 and tryptophan 412 of the HepG2 (Glut1) glucose transporter inhibit transport activity and targeting to the plasma membrane in Xenopus oocytes.

All 6 tryptophan residues in the human HepG2-type glucose transporter (Glut1) were individually altered by site-directed mutagenesis to investigate the role of these residues in transport function. Tryptophan residues in positions 48, 65, 186, 363, 388, and 412 of Glut1 were changed to either a glycine or leucine residue. Mutant mRNAs were synthesized and injected into Xenopus laevis oocytes. Transporter function as assessed by uptake of 2-deoxy-D-[3H]glucose or transport of 3-O-[3H]methylglucose was decreased in the 388 and 412 mutants but was unaltered in all other mutants. The amount of the mutant transporters expressed in total membrane and plasma membrane fractions was measured using Glut1-specific antibodies. Calculation of the intrinsic transport activity of each of the mutants using these data demonstrated that the reduced transport activity of the 412 mutants was caused entirely by a dramatic decrease in the intrinsic activity of the mutant proteins whereas the reduced activity of the 388 mutants was a result of a decreased level of the protein in oocytes, decreased targeting to the plasma membrane, and a modest decrease in the intrinsic activity. Protease/glycosidase mapping of in vitro translation products indicated that the effects of the 388 and 412 point mutations could not be attributed to a disruption in the ability of the mutant proteins to insert properly into the membrane. The ID50 for cytochalasin B inhibition of 2-deoxyglucose uptake was increased from 5 x 10(-7) M for the wild-type Glut1 to 4 x 10(-6) M in the 388 mutants but was unaltered in the 412 mutants. These observations suggest that 1) Trp-412 may comprise part of a hexose binding site or is involved in maintaining a local tertiary structure critical for transport function; 2) Trp-388 is involved in stabilizing the equilibrium binding of cytochalasin B to the transporter. Trp-388 may therefore lie near a substrate binding site and also appears to participate in stabilization of local tertiary structure important for full catalytic activity and efficient targeting to the Xenopus plasma membrane.

Animals↗
PubMed1977

Synthesis of auxins from tryptophan and tryptophan-precursors by fungi isolated from mycorrhizae of pine (Pinus silvestris L.).

Fungi isolated from mycorrhizae of pine required tryptophan for auxin synthesis. More auxins were found in culture grown with pyrogallol than in those without this compound. The fungi studied produced also auxins from other than tryptophan compounds. Indole employed with serine was more suitable for the production of auxins than indole or anthranilic acid used separately. The active compounds showing auxin activity were located on the chromatograms at Rf 0.2--0.4 and 0.3--0.5 with the solvent system isopropanol, ammonia, water (10:1:1 v/v).

Culture Media↗
PubMed1996

gamma-L-glutamyl-5-hydroxy-L-tryptophan, but not gamma-L-glutamyl-L-tryptophan, causes sodium retention in normal man.

1. This randomized, placebo-controlled, cross-over study compared the relative effectiveness of gamma-L-glutamyl-5-hydroxy-L-tryptophan (glu-5-HTP) and gamma-L-glutamyl-L-tryptophan (glu-TRP) in terms of their ability to act as substrates for renal 5-hydroxytryptamine (5-HT) synthesis and their actions on urinary sodium excretion. 2. Urinary excretion of 5-HT and sodium were determined before, during and after 1 h intravenous infusion of an equimolar amount (45 nmol kg-1 min-1) of glu-5-HTP or glu-TRP or placebo in nine healthy male subjects. 3. Cumulative urinary 5-HT excretion over the 4 h after the start of glu-5-HTP infusion was 350-fold greater than that after placebo, and this was associated with a reduction in the urinary excretion of sodium. 4. In contrast, the urinary excretion values of 5-HT and sodium after administration of glu-TRP were not significantly different from those observed on the placebo day. 5. The marked increase in urinary 5-HT excretion and the retention of sodium after administration of glu-5-HTP have been demonstrated in previous studies and result from increased intrarenal generation of 5-HT. The absence of a rise in urinary excretion of 5-HT after glu-TRP infusion suggests that there was no significant conversion of this glutamyl compound to 5-HT within the kidney. As a result, there was no effect on urinary sodium excretion.

5-Hydroxytryptophan↗
PubMed1990

Metabolism of Tryptophan and Tryptophan Analogs by Rhizobium meliloti.

The alfalfa symbiont Rhizobium meliloti Rm1021 produces indole-3-acetic acid in a regulated manner when supplied with exogenous tryptophan. Mutants with altered response to tryptophan analogs still produce indole-3-acetic acid, but are Fix(-) because bacteria do not fully differentiate into the nitrogen-fixing bacteriod form. These mutations are in apparently essential genes tightly linked to a dominant streptomycin resistance locus.

Journal Article↗
PubMed1997

Crystallization and preliminary X-ray analysis of bacteriophage lambda lysozyme in which all tryptophans have been replaced by aza-tryptophans.

After many unsuccessful attempts to crystallize the bacteriophage lambda lysozyme, a mutant where all the tryptophan residues have been replaced by aza-tryptophans has been crystallized by the vapor-diffusion method. The crystals are orthorhombic and belong to space group P2(1)2(1)2(1) with cell dimensions a = 73.01, b = 78.80, c = 82.31 A. Diffraction data were collected using synchrotron radiation sources. Crystals diffract to a resolution of 2.3 A. Data from two different platinum derivatives were also recorded to 2.8 and 2.5 A, respectively.

Journal Article↗
PubMed1994

1,1'-Ethylidenebis[L-tryptophan], a contaminant implicated in L-tryptophan eosinophilia myalgia syndrome, suppresses mRNA expression of hypothalamic corticotropin-releasing hormone in Lewis (LEW/N) rat brain.

The L-tryptophan eosinophilia myalgia syndrome (L-Trp-EMS), related to ingestion of impure L-Trp, occurred in epidemic proportions in the United States in 1989. Epidemiologic studies implicated 1,1'-ethylidenebis[L-tryptophan] (EBT) as the impurity most highly associated with development of human L-Trp-EMS. We have previously shown that Lewis (LEW/N) rats fed L-Trp implicated in the L-Trp-EMS epidemic (case-associated L-Trp) develop fasciitis and perimyositis which is associated with a reduction in corticotropin-releasing hormone (CRH) mRNA expression in the hypothalamic paraventricular nucleus (PVN). In this study, we report the effects of EBT- and case-associated L-Trp on CRH mRNA expression in the hypothalamic PVN and secretion of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) into the plasma over a time course of 1-6 weeks in the same rats in which we have found fascial thickening and immune cell activation induced by these compounds. Both control L-Trp and EBT stimulated the secretion of ACTH and CORT at 1-2 weeks, whereas case-associated L-Trp did not. EBT and case-associated L-Trp decreased CRH mRNA expression in the PVN at 2-6 weeks, while control L-Trp had no effect. The striking contrast in the effects of case-associated L-Trp and EBT on the HPA axis suggests that the reduction in CRH mRNA levels in the PVN seen in each case may be related to different mechanisms. It is possible that EBT suppresses CRH mRNA expression directly, in the absence of inflammation, while case-associated L-Trp may act through multiple mechanisms, including that associated with inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Application of rapid-scanning, stopped-flow spectroscopy to the characterization of intermediates formed in the reactions of L- and D-tryptophan and beta-mercaptoethanol with Escherichia coli tryptophan synthase.

The reactions of the alpha 2 beta 2 complex of Escherichia coli tryptophan synthase with D- and L-Trp and the presteady-state reaction of L-Ser and beta-mercaptoethanol under different premixing conditions have been investigated by rapid-scanning stopped-flow (RSSF) UV-visible spectroscopy. The reaction of alpha 2 beta 2 with L-Ser and beta-mercaptoethanol occurs in 3 detectable relaxations with rates similar to the 3 relaxations seen in the partial reaction with L-Ser and in the reaction with L-Ser and indole. The presteady-state phase of the reaction of beta-mercaptoethanol with the alpha-aminoacrylate intermediate is characterized by 2 relaxations. The RSSF spectra for this reaction show that the spectral changes that take place in these 2 phases are essentially identical. The L-Trp reaction is biphasic, and the spectral changes occurring in each phase of the reaction also are identical. The 2 new spectral bands formed (lambda max congruent to 420 nm and congruent to 476 nm) are assigned as the L-Trp external aldimine (Schiff's base) and L-Trp quinonoid intermediates, respectively. The reaction of D-Trp also is biphasic. Analysis of first and second derivatives of the RSSF spectral changes give evidence for the formation of spectral bands with lambda max of approximately 423 nm, approximately 450 nm, and approximately 478 nm. The positions and shapes of these bands suggest a D-Trp external aldimine structure (423 nm) and a quinonoidal species (450 and 478 nm). However, product studies do not support this latter assignment. The behavior of the D- and L-Trp reactions and the reaction of beta-mercaptoethanol with the alpha-aminoacrylate strongly indicate the pre-existence of 2 slowly equilibrating forms of the internal aldimine and of the alpha-aminoacrylate.

Escherichia coli↗
PubMed1996

Effects of chronic administration and subsequent withdrawal of ethanol-containing liquid diet on rat liver tryptophan pyrrolase and tryptophan metabolism.

An investigation of the effects of chronic administration of ethanol by the liquid diet procedure and its subsequent withdrawal on tryptophan (Trp) metabolism and disposition was performed in rats. Treatment with the control liquid diet caused an enhancement of liver Trp pyrrolase activity and mRNA abundance. These effects are not due to the starvation associated with this feeding procedure, because they occur in rats maintained on the liquid diet ad libitum. Chronic ethanol administration in the liquid diet did not further influence the above increased expression of Trp pyrrolase mRNA but caused inhibition of pyrrolase activity in competition with the effects of the diet. The control liquid diet decreased liver Trp concentration, but exerted no significant effects on other aspects of Trp disposition. The most striking and robust finding was a highly significant elevation in both Trp pyrrolase activity and mRNA expression at 7 h following discontinuation of ethanol availability, at which time there were demonstrable behavioural signs of ethanol withdrawal. The increase in Trp pyrrolase mRNA during alcohol withdrawal may be caused by corticosterone, whose circulating concentration was also increased. The changes in Trp pyrrolase activity during ethanol withdrawal were associated with significant alterations in Trp disposition including decreased brain Trp concentration and 5-hydroxytryptamine synthesis and turnover. These alterations may play a pivotal role in the behavioural manifestations of ethanol withdrawal including the hyperexcitement underlying audiogenic seizures. We suggest that rat Trp pyrrolase gene regulation may be an important biological determinant of the ethanol withdrawal syndrome and requires further study, and that the use of the liquid diet procedure in Trp metabolic studies requires inclusion of adequate controls and special attention to the effects of the liquid diet itself.

Alcohol Withdrawal Delirium↗
PubMed2004

A mass spectrometric and molecular orbital study of H2O loss from protonated tryptophan and oxidized tryptophan derivatives.

Protonated N-acetyltryptophan, oxindolylalanine (a mono-oxidized derivative of tryptophan), and N-acetyloxindolylalanine, as well as several di- and tripeptide derivatives containing oxindolylalanine, undergo a range of fragmentation reactions in the gas phase, including the loss of water. In order to elucidate the sites of water loss within these ions, and to determine the mechanisms associated with these processes, we have conducted a series of experiments employing multistage tandem mass spectrometry (MS/MS and MS(3)) in a quadrupole ion trap mass spectrometer, regiospecific structural labeling, and independent solution-phase syntheses of proposed product ion structures, coupled with the use of molecular orbital calculations at the B3LYP/6-31G* level of theory. We demonstrate that the loss of H(2)O from the amide carbonyl group of protonated N-acetyltryptophan O-methyl ester occurs via a "side-chain-backbone" neighboring group reaction to yield a protonated carboline derivative. In contrast, the loss of water from the O-methyl ester of protonated oxindolylalanine results in the formation of a tricyclic structure by "backbone-side-chain" nucleophilic attack from the amino nitrogen to the C2 position of the indole ring. The O-methyl ester of protonated N-acetyloxindolylalanine was found to dissociate via the loss of water from both possible sites, i.e. from the side-chain indolyl oxygen and the backbone amide carbonyl group. An estimate of the relative preference for water loss from each site was obtained from the abundances of product ions formed from MS(3) analysis of regiospecifically labeled derivatives of N-acetyloxindolylalanine, and from the results of molecular orbital calculations. These studies indicate the absence of a characteristic 'signature' ion or neutral loss for peptides containing oxindolylalanine residues under low-energy ion trap CID conditions.

Models, Molecular↗
PubMed1999

Serum tryptophan to large neutral amino acid ratio and urinary tryptophan in three patients with phenylketonuria in a family. A clinical and biochemical study.

In this work clinical and biochemical findings are presented in three untreated children with phenylketonuria in a family. Their clinical pictures were not typical for classical phenylketonuria. As a result, diagnosis was missed. It has been shown that patterns of large neutral amino acids in serum and urine were somewhat different. Significantly lower serum TRP/LNAA ratio was observed in all patients with phenylketonuria, compared to the control group. These findings suggest that there was subnormal tryptophan availability in the central nervous system leading to its decreased metabolism through the serotonin and kynurenine pathways. These results may explain decreased children's growth and their mental deficiency.

Adult↗
PubMed1999

Determination of tryptophan and tryptophan metabolites in grape must and wine.

Tryptophan (Trp) and its metabolites, especially indole-3-acetic acid (IAA), are considered as potential precursors of 2-aminoacetophenone (AAP), an aroma compound which causes the "untypical aging off-flavor" (UTA) in Vitis vinifera white wines. In this study RP-HPLC with fluorescence detection was used for the qualitative and quantitative analysis of Trp and Trp-metabolites in 39 grapes, 22 grape musts and 16 wines, to which different viticultural conditions (ripeness, pruning, strip of leaves, soil condition) have been applied. A sensitive and selective determination was achieved after solid phase extraction using an anion exchange material. Only traces of Trp-metabolites could be determined in the examined grapes and grape musts, but their amounts increased significantly during fermentation, whereas the amount of Trp decreased. Different viticultural measures, besides the time of grape harvest, showed no significant influences on the amount of Trp and Trp-metabolites.

Acetophenones↗