Urine threonine

The amounts of single amino acids excreted in urine in the conjugated form, as determined independently by Stein and Muting, are given in Tables 1 and 2. According to Stein, glycine, glutamic acid, aspartic acid, histidine, and proline are quantitatively the most important amino acids liberated in the course of urine hydrolysis. Serine, lysine, tyrosine, cysteine and cystine, threonine, alanine, valine, phenylalanine, and leucine are... 

By means of a procedure described above, Hanson and Fittkau (HI) isolated seventeen different peptides from normal urine. One of them, not belonging to the main peptide fraction, consisted of glutamic acid, and phenylalanine with alanine as the third not definitely established component. The remaining peptides contained five to ten different amino acid residues and some unidentified ninhydrin-positive constituents. Four amino acids, i.e., glutamic acid, aspartic acid, glycine, and alanine, were found in the majority of the peptides analyzed. Twelve peptides contained lysine and eight valine. Less frequently encountered were serine, threonine, tyrosine, leucine, phenylalanine, proline, hydroxyproline, and a-aminobutyric acid (found only in two cases). The amino acid composi-... 

Sulfocys sulfocysteine Thr threonine, Tyr tyrosine, u urine, Val valine... 

Fig. 7. Chromatogram of 24-hr urine specimen (sample 1 ml 170 ml/24 hr) in a case of common rachitis in a 9-month-old child (D24). The following features are to be noticed definitely increased excretion of threonine, serine, glycine, and histidine.

As a result of GC-MS analyses, 103 metabolites were determined, of which 66 were successfully identified and 18 were used to create a diagnostic model. Of these 18 metabolites, 5 (suberic acid, glycine, L-tyrosine, L-threonine, and succinic acid) had significantly higher levels in patients with HCC than in healthy volunteers (p < 0.05). Other metabolites (oxalic acid, xylitol, urea, phosphates, propanoic acid, threonine, pimelic acid, butyric acid, trihydroxypentanoic acid, hypoxanthine, arabinofuranose, dipeptide of hydroxyproline, and tetrahydroxypentanoic acid) showed higher levels in healthy volunteers (p < 0.05). In addition, Wu et al. determined the levels of AFP using an ELISA test in serum from the same patients and healthy volunteers as in the metabolomic study of urine samples. An AFP concentration above 20 ng/mL suggests a positive result and the presence of... 

Breakdown of isoleucine, valine, threonine, and methionine results in the production of propionyl-CoA. Propionyl-CoA, in turn, is catabolized to succinyl-CoA via the intermediate methylmalonyl-CoA. Methylmalonyl-CoA is a compoimd of imusual interest to nutritional scientists. This compound accumulates in the cell during a vitamin B12 deficiency. Vitamin B12 deficiency is not a rare disease, as it appears in a common autoimmune disease called pernicious anemia. Vitamin B12 deficiency also occurs in strict vegetarians who avoid meat, fish, poultry, and dairy products. Methylmalonyl-CoA can also build up with rare genetic diseases that involve the production of defective, mutant forms of methylmalonyl-CoAmutase. Most of the methylmalonyl-CoAthat accumulates to abnormally high levels in the cell is hydrolyzed to methylmalonic acid (MMA), which leaves the cell for the bloodstream and eventual excretion in the urine. Some of the MMA is converted back to propionyl-CoA, resulting in the production and accumulation of propionic acid in the cell. The measurement of plasma and urinary MMA has proven to be a method of choice for the diagnosis of vitamin B12 deficiency, whether induced by pernicious anemia or by dietary deficiency. 

The normal pattern of the urine is characterized by the presence of five amino acids which give prominent spots. These are glycine, serine, alanine, glutamine, and histidine. Moderate amounts to traces of lysine, threonine, glutamic acid, taurine, methylhistidine, and j8-aminoiso-butyric acid occur in some normal samples (Fig. 4). Soupart (S42) and Peters et al. (P17) have published data on the urinary excretion of the free amino acids by normal human subjects which provide a useful compilation of the current knowledge in this field (Table 4). 

Other reports of fucosylation have suggested the existence of proteins that contain fucose residues attached directly to a serine or threonine. This linkage was first described by the presence of amino acid fucosides in human urine [121] then as components of rat tissue extracts [122] and rat glycoproteins [123]. Release of the glycans by alkaline 3-elimination revealed the presence of both fucitol and Glc(31-3)fucitol [123]. Further examination of these fucosylated glycoproteins in soluble and membrane fractions from rat cells suggests the existence of both cytosolic and membrane associated O-linked fucosylated proteins [124], but the purity of the cytosolic fractions was never examined. 

More recently, Henning and Ammon (H19) described 10 aliphatic keto and aldehydic adds in normal urine. In addition to a-ketoglutaric, oxalacetic, pyruvic, glyoxylic, and a-ketoisocaproic acids, they found hydroxypyruvic, a-keto-y-methylthiobutyric, a-keto-fi-hydroxybutyric, a-keto-P-methylvaleric and a-keto-n-butyric acids, that is to say, the keto acids corresponding, respectively, to serine, methionine, threonine, isoleucine, and a-amino-n-butyric acid. They conclude that one finds in normal human urine the keto acids corresponding to all the amino adds normally present in urine, with the exception of those correspond-... 

In the disorder that was first observed in the Hailnup family and bears their name, the intestinal and renal transport defect involves the neutral amino acids (monoamine, monocarboxylic acids), including a number of the essential amino acids (isoleucine, leucine, phenylalanine, threonine, tryptophan, and valine) as well as certain nonessential amino acids (alanine, serine, and tyrosine). A reduction in the availability of these essential amino acids would be expected to cause a variety of clinical disorders. Yet children with the Hartnup disorder identified by routine newborn urine screening almost always remain clinically normal. 

Most amino acids cannot be detectai by direct UV monitoring. A procedure was developed for the determination of a mixture of these compounds (proline, glutamine, threonine and tyrosine) in urine, by precolumn formation of the Cu(II) complexes and detection at 235 nm, using a 0.03 M SDS-8% 1-propanol mobile phase at pH 5.5 [25]. 

Methylmalonyl-CoA mutase (EC 5.4.99.2). Failure to convert (/ )-methylmalonyl-CoA into succinyl-CoA. Large quantities of methylmalonic acid appear in plasma and urine. Affected children fail to thrive and show pronounced ketoacidosis. Often fatal in early life. Hyperammonemia and intermittent hyperglycinemia are also typical. Restricted protein intake and synthetic diets are helpful, in particular low intakes of leucine, isoleucine, valine, threonine and methionine. A similar condition may arise from a congenital deficiency of methylmalonyl-CoA epimerase (EC 5.1.99.1). Both conditions unresponsive to vitamin Bj2. Another type of methylmalonyl aciduria is thought to result from an hereditary deficiency of deoxyadenosyl transferase (transfers the 5 -deoxyade-nosyl group in cobalamin synthesis), which provides the coenzyme of methylmalonyl-CoA mutase. This condition responds to injection of B,2. Dietary B12 deficiency also results in methylmalonic aciduria. 

The distribution of amino acids in the blood and urine of patients with kwashiorkor is modified. The total amino acid content of the serum is decreased. The reduction affects some amino acids more than others. For example, the serum is low in arginine, leucine, and threonine, but has a normal content of phenylalanine and tyrosine. The decrease in the amino acid content of the plasma varies considerably with the individual. Mexican authors have claimed that the total amino acid content of the plasma may drop to half of the normal values. 

Galactose linked to serine or threonine has been found and in earthworm cuticula collagen. Futhermore a compound containing the disaccharide glucosyl-3-1.3 fucose joined to threonine has been isolated from urine. 

Small amounts of this amino acid are found to be widely distributed in the nonprotein extracts of tissues by paper chromatography. Dent has reported its appearance in the urine of a patient with hepatic disease following the administration of large amounts of methionine. Lien and Greenberg have shown that is formed from threonine in the animal body. 

Threonine and Serine. Within 3 home after the administration of the racemates of these amino acids, an increase of hydroxyamino-N, equivalent to 30 to 40% of the Z-components of either amino acid, is found in the urine. This finding indicates a partial utilization of the unnatural forms of these hydroiqramino acids (113). 

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