Search results for "Tryptophan"

ARGININE, HISTIDINE AND TRYPTOPHAN IN PEPTIDE SYNTHESIS. THE IMIDAZOLE FUNCTION OF HISTIDINE

1989

Zum Tryptophanabbau bei Cordyceps militaris-Stämmen in saprophytischen Kulturen

1973

Summary The degradation of tryptophan in two strains of the Cordyceps miliraris Link in saprophytic culture was examined: both fungi showed different behavior patterns. In the strain I all the tryptophan is subject to lateral catenoid oxidation and the metabolite of this catabolism process are fixed. In strain II under identical experimental conditions the tryptophan is decomposed by the “Ehrlich-mechanism”. Independently of the above, N-acetylization reactions occur in both strains. Here both the L-isomers and the D-isomers of tryptophan are metabolized. Both isomers can be acetylized.

Two-photon excitation microscopy of tryptophan-containing proteins.

2002

We have examined the feasibility of observing single protein molecules by means of their intrinsic tryptophan emission after two-photon excitation. A respiratory protein from spiders, the 24-meric hemocyanin, containing 148 tryptophans, was studied in its native state under almost in vivo conditions. In this specific case, the intensity of the tryptophan emission signals the oxygen load, allowing one to investigate molecular cooperativity. As a system with even higher tryptophan content, we also investigated latex spheres covered with the protein avidin, resulting in 340 tryptophans per sphere. The ratio of the fluorescence quantum efficiency to the bleaching efficiency was found to vary b…

Effects of Environmental Lighting and Tryptophan Devoid Diet on the Rat Vaginal Cycle

1998

Cerebral serotonin level influences luteinizing hormone release and, consequently, ovulation. The present study evaluated the effects of precooked maize meal (polenta), a diet almost devoid of tryptophan the serotonin precursor on the alterations of the estrus cycle as measured by vaginal smears analysis in Wistar rats. Several conditions of environmental lighting were used in order to modify ovarian cycle: 1) natural alternating light/dark cycle; 2) continuous darkness; 3) continuous light by sodium steams: 4) continuous light by fluorescent neon tubes. Rats bred in continuous lighting showed estrus-proestrus rate significantly greater than rats bred in normal lighting or in continuous dar…

Benzodiazepines: specific competitors for the binding of L-tryptophan to human serum albumin.

1975

By means of the gel filtration technique, the effect of nine benzo-diazepine derivates on the binding of l-tryptophan to human serum albumin was investigated. Using equimolar tryptophan and benzodiazepine concentrations, all benzodiazepines with binding constants higher than 104 (M−1), displace l-tryptophan from its binding site to a high degree. The mechanism of the displacement was characterized as a competition for a common binding site. Some of the benzodiazepines displace l-tryptophan to a greater extent than salicylic acid. The benzodiazepines and tryptophan are the only substances known with a high degree of stereospecific binding to human serum albumin. This study shows that there i…

Ischemic type biliary lesions in histidine-tryptophan-ketoglutarate (HTK) preserved liver grafts.

2006

Ischemic type biliary lesions lead to considerable morbidity following orthotopic liver transplantation. The exact pathogenesis is unknown. One major hypothesis is that insufficient perfusion of the arterial vessels of the biliary tree, especially under perfusion with the high viscous University of Wisconsin solution, might be responsible for ischemic type biliary lesions. Due to low viscosity, HTK solution is reported to have a lower incidence of biliary complications. However, there is no data concerning ischemic type biliary lesions in HTK preserved livers. In this paper we report our results after orthotopic liver transplantation with special regard to ischemic type biliary lesions in …

Cardiovascular and Endocrine Properties of L-Tryptophan in Combination with Various Diets

1991

Brain serotonin neurons are intimately involved in a number of relevant physiological functions such as cardiovascular regulation, neuroendocrine output from the anterior pituitary (e.g. ACTH, prolactin), regulation of behavior (e.g. agression, sleep, locomotor and sexual behavior), mood or appetite control (Fernstrom, 1983; Lehnert et al., 1987; Spring et al., 1987; Wurtman, 1987). The synthesis of brain serotonin is dependent on the availability of the large neutral amino acid L-tryptophan that is hydroxylated to 5-L-hydroxytryptophan and subsequently decarboxylated to yield serotonin. The rate-limiting enzyme tryptophan hydroxylase has a Michaelis constant of approximately 2–3 x 10−5 M w…

Tryptophan Fortification of Adapted Formula Increases Plasma Tryptophan Concentrations to Levels Not Different from Those Found in Breast-Fed Infants

1992

Several recent studies have demonstrated significantly lower plasma total tryptophan concentrations in formula-fed than in breast-fed infants. We have measured preprandial plasma amino acid concentrations in infants breast-fed or fed a formula with a protein concentration of 1.57 g/dl and with a whey/casein ratio of 60:40 or a formula with a protein concentration of 1.37 g/dl and a whey/casein ratio of 40:60 and fortified with 10 mg/dl (15 mg/100 kcal) of tryptophan. Healthy term infants (10 per group) were either breast-fed from birth or randomly assigned to one of the two study formulas. At 4 and 12 weeks of age, anthropometric measurements were performed and blood samples were obtained. …

Immunoadsorption with tryptophan columns: A therapeutic option for the treatment of rheumatoid arthritis with septic complications

2009

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease affecting multiple organs and tissues. Although there is a wide range of therapeutic applications, the coexistence of severe side effects and contraindications outlines the necessity of new therapeutic options in the treatment of severe RA. We report on the case of a 71-year-old patient with successful treatment of a complicated RA with tryptophan immunoadsorption combined with low-dose steroids. Bacterial spondylitis developed in this patient during long-term treatment with infliximab and methotrexate. Weekly immunoadsorption sessions with tryptophan columns resulted in continuous suppression of RA activity over a perio…

Fighting the Consequences of the COVID-19 Pandemic: Mindfulness, Exercise, and Nutrition Practices to Reduce Eating Disorders and Promote Sustainabil…

2023

Over the past two years, the world’s population has been tested by the COVID-19 health emergency. This has changed population habits worldwide by encouraging a sedentary lifestyle and overnutrition. Isolation and reduction of social life, for most of the population, was mandatory but it quickly became a new lifestyle. Nowadays, we are encountering the consequences with an increase in nutritional associated disorders and conditions that cause illnesses in the general population. These disorders include diet excesses that lead to obesity and diet deficiencies and malnutrition which could rapidly lead to death. These eating disorders are very complex to manage because they become mental disord…