threonine

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threonine

(thrē`ənēn), organic compound, one of the 22 α-amino acidsamino acid
, any one of a class of simple organic compounds containing carbon, hydrogen, oxygen, nitrogen, and in certain cases sulfur. These compounds are the building blocks of proteins.
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 commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. It is one of several essential amino acids needed in the diet; human beings cannot synthesize it from simpler metabolites. Young adults need about 14 mg of this amino acid per day per kilogram (6 mg per lb) of body weight. Although threonine participates in many reactions in bacteria, including the biosynthesis of vitamin B12 and isoleucineisoleucine
, organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein.
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, its metabolic role in higher animals, including man, remains obscure. It is known only as a constituent of proteins, and even in that form it is relatively unreactive. In spite of the fact that its side chain has a hydroxyl group similar to that of serineserine
, organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein.
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, there is no indication that it participates in the catalytic functions of any enzyme. Threonine was isolated from the protein fibrin in 1935 and synthesized in the same year.

Threonine

 

α-amino-β-hydroxybutyric acid, a natural amino acid, CH3CH(OH)CH(NH2)COOH. It exists in four optically active forms and two racemates (L-, D-, and DL-threonine and L-, D-, and DL-allothreonine). Natural L-threonine was isolated in 1935 from acid hydrolysates of fibrin. L-threonine constitutes 2–6 percent of all natural proteins, except protamines.

Threonine is an essential amino acid. The daily requirement for adults is 0.5 g, and for children up to the age of 7, about 3 g. The precursor of L-threonine during biosynthesis in plants and microorganisms is aspartic acid. This multistage enzymic process is regulated according to the feedback principle: excess threonine inhibits the first enzyme on the path to the biosynthesis of threonine. There are various possible pathways for the decomposition of threonine in the body; they lead to the formation of a-ketobutyric acid, acetaldehyde, and glycine, as well as pyruvic acid.

A method for the chemical synthesis of L-threonine from acetaldehyde and glycine has been developed.

REFERENCE

Meister, A. Biokhimiia aminokislot. Moscow, 1961. (Translated from English.)

E. N. SAFONOVA

threonine

[′thrē·ə‚nēn]
(biochemistry)
CH3CHOHCH(NH2)COOH A crystalline α-amino acid considered essential for normal growth of animals; it is biosynthesized from aspartic acid and is a precursor of isoleucine in microorganisms.
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Asi, encuentra que mientras que las empleadoras demandan THR para poder ofrecer su mano de obra al mercado, las trabajadoras del hogar se apoyan en familiares para las tareas de cuidado en sus propios hogares.
All studied parameters were higher for animals supplemented with Thr in ovo (T) (p [less than or equal to] 0.05), but crypt depth was not different (p > 0.05).
In conclusion, we estimate that the dietary Thr requirement is 0.57% to achieve the maximum egg production, egg mass, and feed utilization relative to the egg mass, while a level of 0.58% is required to obtain the maximum egg weight in Longyan ducks from 17-45 wk of age.
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Also, the actor said that Jake has lost the trust because "he failed with the Maya Pope thing, ran off with Olivia at Fitz's darkest moment and took advantage of that and manipulated her in Fitz's view." Goldwyn told THR that when evidence against Jake surfaces, Fitz's "complicated feelings about Olivia" and the "way Jake has failed him" have made him only trust Rowan.
Analogous to phosphorylation, O-glycosylation is also one of the important PTMs during which N-acetyl-glucosamine (O-GlcNAc) molecule is introduced on Thr or Ser residue by O-GlcNAc transferase (OGT).
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