Dietary and other sources

Foods contain Trp. mostly bound in proteins. 5-hydroxytryptophan. >hydroxy!ryplain me (5-I1T). and tryptamine: synthetic supplements sometimes contain tryptophan ethyl ester whose uptake is not limited by Hortnup disease (Anonymous, 1990). Foods containing significant amounts of5-1 IT include bananas (0.02 mg g). pineapples, and walnuts (Ifelander and Some, 2000).

Milk protein is relatively more rich in Irp {14.1 mgg protein) than eggs (12.2mg'g), white bread (II.7 mg g) or beef (11.2 mg g); corn contains much less (7mg/g). High heat can induce the condensation ofTrp with aldohexoses and thereby generate various Amadori rearrangement products, including N( 1 )-(bela-d-hexopyranosyl )-l-trypto-phan. 2-(beta-d-hexopyranosy 1)-1-tryptophaii and l-( 1.2.3.4.5-pentahydroxypent-l-yl)-1,2,3,4-tetrahydro-beta-carboline-3-carboxy 1 ic acid derivatives (Gutsche et ai, 1999); thus, grilling, frying, and possibly other types of cooking, can reduce the Trp content of foods (Dworschak, I9K0). The comutagenic Trp deriv ativ e norharman can form ai relatively low temperatures in heat-processed food (Ziegenhagen et al.. 1999), Another important mechanism ofTrp loss during healing (e.g. in ultrahigh-temperature-treated milk) is oxidation, particularly in the presence of iron or copper (Birlouez-Aragon et al., 1997),

Alate: Eosinophilic myalgia syndrome (EMS) with symptoms that include fatigue, pain, depression, sleep disturbance, and verbal memory impairment, can be caused by

membrane membrane endothelium

Figur* R.40 Intestinal absorption ofL-tryptophan membrane membrane endothelium

Figur* R.40 Intestinal absorption ofL-tryptophan

Trp contaminated with one or more of at least six compounds including 2-f3'-indolvl-methyl^indole (Müller et a!., 1999), 3a-hydroxy-t,2,3,3a,8,8a-hexahydropyrrot0-[2-3b]-indolc-2-carboxylic acid and 2-(2-hydroxy-indoline)-tryptophan (Navlor et a!., 1999), and a family of 234 I Ja compounds (Klarskov et al., 1999). Some of these EMS-relatcd contaminants are also present in commercial preparations of 5-hydroxy-tryptophan (Klarskov er al.. 1999) and melatonin (Laforcc et al.. 1999), EMS may have developed in patients sutTering primarily from EMS as an allergic reaction towards a more immunogenic L-tryptophan preparation l Barth el al.. 1999).

Digestion and absorption

Mastication of foods in the mouth, denatumtion by hydrochloric acid and unspccilic protein hydrolysis by pepsin in the stomach initiate breakdown ofTrp-containing proteins.

Pancreatic proteases and intestinal brush border aminopetidases can then generate the free Trp as well as di- and tripeptides that are suitable for absorption. Di- and tripeplitles are taken up via the hydrogen ion peptide coi ran sport or ( SLC15 AI. PepT I ). The sodhtm-amino acid ««transport system B° is the main conduit for intestinal uptake of free Trp ( Avissar ci al.. 20(11 ): the molecular tie feet responsible for impaired uptake in 1 lartnup disease is likely to concern system B". Exchange for other neutral amino acids \ ia the sodium*independent transporter complex BAT ! -rBAT (SLC7A9-SLC3 A1 ) augments this pathway (Verrey et ai. 1999: Mi/oguchi et ai, 2001 ). The l-typc amino acid transporter 1 (TAT1 ) facilitates ion-independent diffusion across the basolateral membrane of cntcrocytes in jejunum, ileum, anil colon (Kim et ai, 2001). Additional transport capacity is provided by the 4F2-glycoprote in-anchored exchanger LAT2 (Rossier et al.. 1999: Rajan e/o/, 2000),

Understanding And Treating Autism

Understanding And Treating Autism

Whenever a doctor informs the parents that their child is suffering with Autism, the first & foremost question that is thrown over him is - How did it happen? How did my child get this disease? Well, there is no definite answer to what are the exact causes of Autism.

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