Mitogen-activated protein kinase kinase 1 (MKK1), a dual-specificity tyrosine/threonine protein kinase, has been shown to be phosphorylated and activated by the raf oncogene product as part of the mitogen-activated protein kinase cascade. Here we report the phosphorylation and inactivation of MKK1 by phosphorylation on threonine 286 and threonine 292. MKK1 contains a consensus phosphorylation s...

The cytotoxicity of overexpressed transporters limits their application in biochemical production. To overcome this problem, we developed a feedback circuit for L-threonine production that uses biosensor to regulate transporter expression. First, used IPTG-induced rhtA regulation, exporter, simulate dynamic regulation improving production, and the results show it had significant advantages comp...

Reduction in the amounts of activity of the first enzyme, aspartokinase (EC 2.7.2.4) and two branch-point enzymes, dihydrodipicolinic acid synthase (EC 4.2.1.52) and homoserine dehydrogenase (EC 1.1.1.3), located in the pathway for the synthesis of aspartate-family amino acids, occurred when cell suspension cultures of Daucus carota L. var. Danvers were grown in media containing 2 mM threonine ...

To characterise the effects of dietary protein content on threonine metabolism during pregnancy, rats were fed diets containing 18% or 9% protein and then killed at different stages of gestation. Serum threonine concentrations fell significantly faster in the animals fed the diet containing 9% protein when compared to those fed the diet containing 18% protein. On day 4 of gestation the rate of ...

The catabolic or biodegradative threonine dehydratase (E.C. 4.2.1. 16) of Escherichia coli is an isoleucine feedback-resistant enzyme that catalyzes the degradation of threonine to alpha-ketobutyrate, the first reaction of the isoleucine pathway. We cloned and expressed this enzyme in Corynebacterium glutamicum. We found that while the native threonine dehydratase of C. glutamicum was totally i...

Concerted feedback inhibition of aspartokinase activity from Pseudomonasfluorescens by the combination of L-threonine and r.-lysine, or by L-threonine and L-methionine was freely and rapidly reversible. Inhibition by L-threonine, or by the concerted pairs of amino acids was kinetically “mixed” with respect to L-aspartate and noncompetitive with regard to ATP. In the presence of L-threonine the ...

Seven homoserine, 42 methionine, 42 threonine, and 15 isoleucine auxotrophs were obtained from Brevibacterium flavum No. 2247 (ATCC No. 14067) by X-ray irradiation and N-methyl-N'-nitro-N-nitrosoguanidine treatment. Concerning the L-lysine-producing ability, the homoserine auxotrophs were the best and about one-half of the threonine auxotrophs ranked next. The rest of threonine auxotrophs and a...

L-Threonine dehydrogenase (L-threonine:NAD+ oxidoreductase (EC 1.1.1.103) has been purified to apparent homogeneity from chicken liver mitochondria. The presence of 2-mercaptoethanol and glycerol is necessary for stabilizing the enzyme during purification and storage. The enzyme is a monomer and has Mr approximately equal to 88,000. The pH optimum is 8.6 to 8.7, and the isoelectric point of the...