Disease relevance of threonine

• One hundred and sixteen crossbred male chicks were used in two battery trials to establish the biological efficacy and toxicity of D-allothreonine (D-allo-Thr) relative to L-Thr [1].
• Protoplasts were prepared from Streptococcus sanguis and some S. mutans serotypes by use of lysozyme (EC 3.2.1.17) under particular conditions: cells had to be grown in DL-threonine (20 mM) and harvested in early exponential phase [2].

High impact information on threonine

• At pH 7.8 and 25 degrees C, the specificity constants (kcat/Km) were as follows: D-serine (3.4 X 10(5) M-1 s-1), D-threonine (2.9 X 10(4) M-1 s-1), D-allothreonine (7.5 X 10(3) M-1 s-1), and L-serine (38 M-1 s-1) [3].
• Neither mutation significantly changed the structure of SHMT, the spectral properties of its complexes, or the kinetics of the retroaldol cleavage of allothreonine and 3-phenylserine [4].
• The pronounced broadening of the DL-threonine carboxyl peak in the presence of the Mn(II)-enzyme complex indicates that an L-threonine binding site is close to the metal binding site of the kinase active site [5].
• Therefore, studies on protein kinase C and these phospholipids were conducted in hepatocytes of rats maintained on three different diets viz. casein (20% protein) deficient (4% protein, rice flour as source of protein) and supplemented (deficient diet supplemented with L-lysine and DL-threonine) diet for 28 days [6].
• Lysozyme treatments to weaken the cell wall and possibly mimic the effect of DL-threonine did not yield any transformants [7].

Biological context of threonine

• A consistent racemization occurred during the acylation of H-His-Pro-Gly-Tyr(Bzl)-OBzl with Z-Val-[GalNAc(Ac)3-alpha]Thr-OH by the BOP-HOBt procedure and the D-allothreonine containing glyco-hexapeptide was isolated in about 20% yield [8].
• Supplementation of the growth medium with glycine, or particularly DL-threonine, produced cells that could be electrotransformed much more efficiently at frequencies up to 2.5 x 10(3) transformants per microgram plasmid DNA [7].

Analytical, diagnostic and therapeutic context of threonine

• The resolution of DL-threonine was performed by preferential crystallization experiments in aqueous solution varying several process parameters like supersaturation, seed amount, initial enantiomeric excess, and scale [9].
• A more complex biochemical explanation of the enhancement of electroporation by growth in DL-threonine is likely, and this is discussed [7].

References