| Description | Dihydrothymine, also known as 5,6-dihydro-5-methyluracil or 5,6-dihydrothymine, (S)-isomer, is a member of the class of compounds known as hydropyrimidines. Hydropyrimidines are compounds containing a hydrogenated pyrimidine ring (i.e. containing less than the maximum number of double bonds.). Dihydrothymine is soluble (in water) and a very weakly acidic compound (based on its pKa). Dihydrothymine can be found in a number of food items such as hyssop, arrowroot, nopal, and red rice, which makes dihydrothymine a potential biomarker for the consumption of these food products. Dihydrothymine can be found primarily in blood, cerebrospinal fluid (CSF), saliva, and urine, as well as in human prostate tissue. Dihydrothymine exists in all living organisms, ranging from bacteria to humans. In humans, dihydrothymine is involved in the pyrimidine metabolism. Dihydrothymine is also involved in few metabolic disorders, which include beta ureidopropionase deficiency, dihydropyrimidinase deficiency, MNGIE (mitochondrial neurogastrointestinal encephalopathy), and UMP synthase deficiency (orotic aciduria). Moreover, dihydrothymine is found to be associated with beta-ureidopropionase deficiency and dihydropyrimidinase deficiency. Dihydrothymine is a non-carcinogenic (not listed by IARC) potentially toxic compound. Dihydrothymine is an intermediate in the metabolism of thymine . Dihydropyrimidine dehydrogenase catalyzes the reduction of thymine to 5, 6-dihydrothymine then dihydropyrimidinase hydrolyzes 5, 6-dihydrothymine to N-carbamyl-b-alanine. Finally, beta-ureidopropionase catalyzes the conversion of N-carbamyl-b-alanine to beta-alanine. Accumulation of dihydrothymine in the body has been shown to be toxic (T3DB). |
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