Threonine is the only amino acid critically required for the pluripotency of mouse embryonic stem cells (mESCs), but the detailed mechanism remains unclear. We found that threonine and S-adenosylmethionine (SAM) metabolism are coupled in pluripotent stem cells, resulting in regulation of histone methylation. Isotope labeling of mESCs revealed that threonine provides a substantial fraction of bo...

The micro-organism LC, isolated from the sheep rumen by Elsden, Volcani, Gilchrist & Lewis (1956), ferments a variety of substrates to yield volatile fatty acids (Elsden & Lewis, 1953). Washed cells of the organism fermented L-threonine and L-serine. Hydrogen, carbon dioxide and ammonia were produced from both substrates and, in addition, propionate was formed from threonine and acetate from se...

None of the remaining 67 isolates utilized aminoacetone when washed suspensions of the bacteria grown on L-threonine were incubated under standard conditions (Higgins et al., 1968). It was concluded that none of the 83 isolates metabolized L-threonine via aminoacetone. Additional work (S. C. Bell & J. M . Turner, unpublished work) suggests that all the selected isolates possessing high L-threon...

The Trypanosoma brucei procyclic form resides within the digestive tract of its insect vector, where it exploits amino acids as carbon sources. Threonine is the amino acid most rapidly consumed by this parasite, however its role is poorly understood. Here, we show that the procyclic trypanosomes grown in rich medium only use glucose and threonine for lipid biosynthesis, with threonine's contrib...

The recent formulation (1, 2) of the structure of vitamin Brz prompts us to report an investigation conducted several years ago on the origin of its aminopropanol component. Previous studies on the metabolism of L-threonine in rats had shown that it was cleaved mainly to acetate and glycine (3,4). The decarboxylation of threonine to the corresponding amine could not be demonstrated, within the ...

The metabolism of (14)C-labeled aspartic acid, diaminopimelic acid, malic acid and threonine by isolated pea (Pisum sativum L.) chloroplasts was examined. Light enhanced the incorporation of [(14)C] aspartic acid into soluble homoserine, isoleucine, lysine, methionine and threonine and protein-bound aspartic acid plus asparagine, isoleucine, lysine, and threonine. Lysine (2 millimolar) inhibite...

The enzyme L-threonine dehydrogenase catalyses the NAD(+)-dependent conversion of L-threonine to 2-amino-3-ketobutyrate, which is the first reaction of a two-step biochemical pathway involved in the metabolism of threonine to glycine. Here, the crystallization and preliminary crystallographic analysis of L-threonine dehydrogenase (Tk-TDH) from the hyperthermophilic organism Thermococcus kodakar...

Two threonine-requiring mutants with derepressed expression of the threonine operon were isolated from an Escherichia coli K-12 strain containing two copies of the thr operon. One of them carries a leaky mutation in ilvA (the structural gene for threonine deaminase), which creates an isoleucine limitation and therefore derepression of the thr operon. In the second mutant, the enzymes of the thr...

A growth study was conducted to determine the dietary threonine requirement of juveniles of the Indian major carp (Cirrhinus mrigala) known as “mrigal”. Diets containing casein and gelatin as sources of intact proteins were supplemented with crystalline amino acids to obtain a crude protein content of 40%. Six diets with different levels of threonine (1.0, 1.3, 1.5, 1.7, 1.9 and 2.1%) were fed ...

1. Clostridium pasteurianum was grown on a synthetic medium with the following carbon sources: (a) (14)C-labelled glucose, alone or with unlabelled aspartate or glutamate, or (b) unlabelled glucose plus (14)C-labelled aspartate, glutamate, threonine, serine or glycine. The incorporation of (14)C into the amino acids of the cell protein was examined. 2. In both series of experiments carbon from ...