The protein profile of Theobroma cacao L. seeds as obtained by matrix-assisted laser desorption/ionization mass spectrometry.

The water-soluble protein profile of the seeds of green, red, and yellow Theobroma cacao L. fruits has been determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS). The seeds were powdered under liquid nitrogen and defatted.

Effects of PEG-interferon alpha plus ribavirin on tryptophan metabolism in patients with chronic hepatitis C.

The currently recommended therapy for chronic hepatitis C (HCV) is a combination of pegylated interferon-alpha (PEG-IFN alpha) and ribavirin. Psychiatric disorders, including depression, are frequent in HCV patients under therapy. We investigated the effect of the antiviral treatment on tryptophan (Trp) metabolism along both serotonin pathway (via 5-hydroxytryptophan, 5-HTP) and kynurenine (Kyn) pathway and on the onset of depressive symptoms in patients with HCV.

A study of tryptophan metabolism via serotonin in ventricular cerebrospinal fluid in HIV-1 infection using a neuroendoscopic technique.

In this paper we report the study of tryptophan metabolism via serotonin in ventricular CSF in HIV-1 infection in order to investigate the origin of tryptophan metabolites in the human brain. The patients (n=4) were affected with non-communicating hydrocephalus. One of these also was suffering from HIV-1 infection.

Ventricular cerebrospinal fluid melatonin concentrations investigated with an endoscopic technique.

The role of melatonin in humans still remains unclear. Uncertainties persist about its effects on neurophysiology regarding its levels in human cerebrospinal fluid (CSF), as the bulk of knowledge on this subject mainly derives from studies conducted on animals. In this study, CSF was micro-sampled with a simple, new method from each cerebral ventricle of patients undergoing neuroendoscopy for hydrocephalus.

A mass spectrometric investigation on the possible role of tryptophan and 7-hydroxytryptophan in melanogenesis.

The activity of tyrosinase and peroxidase + H2O2 in promoting melanogenesis from tryptophan (Trp) and 7-hydroxytryptophan (7-HTP) has been investigated. The reaction samples have been drawn at different reaction times and analysed by MALDI mass spectrometry. The data obtained showed that tryptophan undergoes, under tyrosinase and peroxidase action, an oligomerization process mainly due to the reaction of anthranilic acid (AA) and Trp.

Study of tryptophan metabolism via serotonin in cerebrospinal fluid of patients with noncommunicating hydrocephalus using a new endoscopic technique.

By a recent minimally invasive neuroendoscopic technique, the cerebral ventricles have been reached in a quick, reliable, and harmless way, making possible the study of cerebrospinal fluid (CSF) of the lateral ventricles and, above all, the CSF adjacent to the walls of the third ventricle. Tryptophan, 5-hydroxytryptophan, serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were measured in CSF by HPLC equipment. Twenty-six patients affected with noncommunicating hydrocephalus were enrolled in the study and, as controls, 28 subjects not suffering from any neurological disease.

Influence of age on Cu/Zn-superoxide dismutase and indole 2,3-dioxygenase activities in rat tissues.

The aim of this study was to investigate in vitro the variations with age of the activities of the two antioxidant enzymes Cu/Zn-superoxide dismutase (SOD) and indole 2,3-dioxygenase (IDO) in metabolically active tissues of rats of various ages. In rats aged one week and 2-3 months the highest Cu/Zn-SOD activity was found in the liver and the lowest in the small intestine. At 12 and 18 months of age, the activity was higher in the brain and kidneys, when compared to the small intestine, lungs and liver.

An investigation on the possible role of melatonin in melanogenesis.

The possible role of melatonin in melanogenesis was investigated by performing reactions of melatonin with peroxidase + H2O2 or H2O2 only, in the presence or absence of UV irradiation. Samples of the reaction mixtures were drawn at different times (from 15 to 480 min), the enzyme (when present) was removed by ultrafiltration and the samples so obtained were analyzed by MALDI/MS. The results show that melatonin undergoes oligomerization reaction with peroxidase + H2O2, leading to heptameric species.

Cloricromene effect on the enzyme activities of the tryptophan-nicotinic acid pathway in diabetic/hyperlipidemic rabbits.

Since alterations of tryptophan metabolism have been reported in diabetes and atherosclerosis, it was thought of interest to investigate any role of cloricromene through the influence on the oxidative metabolism of the amino acid by using diabetic/hyperlipidemic rabbits. Male 4-month-old New Zealand white rabbits, fed a diet enriched with 1% cholesterol and 10% corn oil, were made diabetic with alloxan. During the hyperlipidemic diet, a group of rabbits was treated with cloricromene (10 mg/kg/day subcutaneously plus 1.

The effect of age on the enzyme activities of tryptophan metabolism along the kynurenine pathway in rats.

Background: Quinolinic acid and other kynurenine metabolites of the oxidative metabolism of tryptophan play an important role in several pathophysiological conditions. We aimed to study the effect of age on the enzyme activities of tryptophan metabolism along the kynurenine pathway.

Methods: Enzyme activity was investigated in liver, kidneys and small intestine obtained from Sprague-Dawley rats of various ages (1 week, 2-3, 12 and 18 months).

Tryptophan metabolism along the kynurenine pathway in diet-induced and genetic hypercholesterolemic rabbits.

Background: The activity of nicotinic acid in hypercholesterolemia has been poorly understood. In man, nicotinic acid derives for the most part from tryptophan along the tryptophan-nicotinic acid pathway, also called the kynurenine pathway, kynurenine being the key metabolite in this process. In the present paper, we investigated if, in animals with hypercolesterolemia, degradation of tryptophan to nicotinic acid along the kynurenine pathway was perturbated.

An investigation on the role of 3-hydroxykynurenine in pigment formation by matrix-assisted laser desorption/ionization mass spectrometry.

In order to investigate the role of tryptophan and its metabolites in biogenesis of melanins, a study on the enzymatic reaction of 3-hydroxykynurenine with tyrosinase and peroxidase was performed. The reaction at different pH values was monitored by sampling at different times, with ultrafiltration used before analysis by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The data obtained in this way showed that oligomerization processes take place with both enzymes, but with different behaviour, also depending on pH.

Serum tryptophan and 5-hydroxytryptophan at birth and during post-partum days.

Serum levels of tryptophan (Trp) and 5-hydroxytryptophan (5-HTP) were measured in the mother at birth, by normal delivery or cesarean section, on days 1 and 3 post-partum, and in the cord blood of the fetus-newborns. Decreases in Trp and 5-HTP levels during delivery were noted. Conversely, Trp levels in the cord blood of fetus-newborns were significantly higher than those of their mothers, and 5-HTP levels also showed a tendency to increase , whereas on day 1 post-partum Trp values were lower than those in fetal cord, but higher than those during spontaneous delivery.

Involvement of 5-hydroxytryptophan in melanogenesis.

Tyrosine is generally considered to be the physiological precursor of melanins and tyrosinase the enzyme responsible. However, recent studies have shown that also peroxidases are involved in the biosynthesis of melanins. These enzymes use hydrogen peroxide to oxidise various phenol substrates.

Antiproliferative effect of indigoid pigments isolated from human urine.

Two indigoid pigments, red indirubin and blue indigotin, were isolated from the urine of healthy male subjects. The two pigments were assayed on HL60 (human promyelocytic cell line) cells. Preliminary results revealed the antiproliferative effect of the pigments.

Enzyme activities along the kynurenine pathway in mice.

Tryptophan metabolism was studied in adult male Swiss mice by determining enzyme activities along the kynurenine pathway. The following enzymes were assayed: liver tryptophan 2,3-dioxygenase, small intestine indole 2,3-dioxygenase, liver and kidney kynurenine 3-monooxygenase, kynureninase, kynurenine-oxoglutarate transaminase, 3-hydroxyanthranilate 3,4-dioxygenase, and aminocarboxymuconate-semialdehyde decarboxylase. Liver tryptophan 2,3-dioxygenase was present only as a holoenzyme: similar results were obtained in the absence or in the presence of the cofactor haematin.

Tryptophan metabolism along the kynurenine pathway in rats.

Enzyme activities along the kynurenine pathway, liver tryptophan 2,3-dioxygenase, small intestine indole 2,3-dioxygenase, liver and kidney kynurenine 3-monooxygenase, kynureninase, kynurenine-oxoglutarate transaminase, 3-hydroxyanthranilate 3,4-dioxygenase, and aminocarboxymuconate-semialdehyde decarboxylase, involved in the catabolism of tryptophan, were studied in male adult Wistar albino rats. Intestine superoxide dismutase and serum tryptophan were also determined. Hepatic tryptophan 2,3-dioxygenase is present both as holoenzyme and apoenzyme, but the total activity is inferior to that of intestine indole 2,3-dioxygenase which, therefore, actively oxidizes tryptophan in rats.

Tryptophan metabolism in rabbits.

Enzyme activities involved in tryptophan metabolism along the kynurenine pathway were studied in male New Zealand white rabbits. Activities are expressed both as specific activity and per g of fresh tissue. Liver tryptophan 2,3-dioxygenase activity (TDO), when assayed in either the absence (holoenzyme) or presence of added haematin (apoenzyme), did not change.

Kynurenine pathway enzymes in guinea pigs.

In some animals, the administration of repeated doses of tryptophan can cause death. It has been reported that guinea pig does not survive repeated doses of tryptophan, due to the absence of the hormonal induction mechanism of liver tryptophan 2,3-dioxygenase (TDO). Therefore, it was of interest to investigate if guinea pig is an animal model suitable for studying tryptophan metabolism.

Kynurenine pathway enzymes in different species of animals.

Kynurenine pathway enzyme activities, liver tryptophan 2,3-dioxygenase (TDO), small intestine indole 2,3-dioxygenase (IDO), liver and kidney kynurenine 3-monooxygenase, kynurenine-oxoglutarate transaminase, kynureninase, 3-hydroxyanthranilate 3,4-dioxygenase and aminocarboxymuconate-semialdehyde decarboxylase, were assayed in rabbits, rats, mice and guinea pigs. Their activities varied among species. Especially, TDO was present as both holoenzyme and apoenzyme only in rat, while the other species, rabbit, mouse and guinea pig, only showed holoenzyme activity.

Metabolism of tryptophan along the kynurenine pathway in alloxan diabetic rabbits.

Enzyme activities along the kynurenine pathway were assayed in the tissues of New Zealand white rabbits made diabetic with alloxan treatment and hypercholesterolemic with a high-cholosterol diet. Activities are expressed as nmoles of product forming per min per mg of protein and per g of fresh tissue. Liver tryptophan 2,3-dioxygenase (TDO) was present only in holoenzyme form.

The kynurenine pathway enzymes in healthy and hyperlipidemic rabbits.

Tryptophan metabolism along the kynurenine pathway in normolipidemic and diet-induced hyperlipidemic New Zealand rabbits was studied. The activities of liver tryptophan 2,3-dioxygenase small intestine indole 2,3-dioxygenase, liver and kidney kynurenine 3-monooxygenase, kynurenine-oxoglutarate transaminase, kynureninase, 3-hydroxyanthranilate 3,4-dioxygenase and aminocarboxymuconate semialdehyde decarboxylase (picolinic carboxylase) were determined. Liver tryptophan 2,3-dioxygenase (TDO) was present only as a holoenzyme.

Enzyme activities of tryptophan metabolism along the kynurenine pathway in various species of animals.

The purpose of this study was to investigate variations in the enzyme activities of the kynurenine pathway in various mammals (rabbit, mouse, rat, guinea-pig). Liver tryptophan 2,3-dioxygenase, small intestine indole 2,3-dioxygenase, liver and kidney kynurenine 3-monooxygenase, kynureninase, kynurenine-oxoglutarate transaminase, 3-hydroxyanthranilate 3,4-dioxygenase and aminocarboxymuconate-semialdehyde decarboxylase were analysed. Small intestine superoxide dismutase activity and free and total serum tryptophan were also measured.

Enzyme activities along the tryptophan-nicotinic acid pathway in alloxan diabetic rabbits.

Recent data from our laboratory have indicated that the rabbit is a suitable animal model for the study of enzyme activities of the tryptophan-nicotinic acid pathway. We report here the pattern of tryptophan metabolism in rabbits made diabetic with alloxan treatment, and hypercholesterolemic with a high-cholesterol diet. A group of rabbits with only hypercholesterolemia was also considered.