Authors:T. Veresegyházy, Hedvig Fébel, and Ágnes Rimanóczy
The absorption of three amino acids (leucine, alanine and lysine) from the washed, closed rumen was studied in a short-term (75 min) experiment in situ. The concentration of leucine and alanine did not change in the rumen during the experiment, while that of lysine continuously decreased, and 40% of the total lysine placed in the rumen was absorbed during the experimental period. The rate of absorption decreased in proportion to the fall of amino acid concentration.
Authors:T. Martins, J. Matos, G. Vicentini, and P. Isolani
Rare earth picrate complexes
with L-leucine (Leu) were synthesized and
characterized. Elemental analysis (CHN), EDTA titrations and thermogravimetric
data suggest a general formula RE(pic)32Leu⋅5H2O
(RE=La–Lu, Y and pic=picrate).
IR spectra indicate the presence of water and suggest that L-leucine is coordinated
to the central ion through the nitrogen of the aminogroup. The absorption
spectrum of the solid Nd compound indicates that the metal-ligand bonds show
a weak covalent character. Emission spectra and biexponential behavior of
the luminescence decay of the Eu compound suggest the existence of polymeric
species. Thermal analysis results indicate that all the compounds present
a similar behavior, with five major thermal decomposition steps. The final
products are rare earth oxides. A slow heating rate is necessary to observe
all decomposition steps.
Enthalpies and entropies of sublimation for N-acetylglycine amide (NAGA), N-acetyl-L-alanine amide (L-NAAA), and N-acetyl-D-leucine amide (D-NALA) were determined from the dependence of their vapour pressures on temperature, as measured by the torsion-effusion method.
Authors:Edward Onyango, Elikplimi Asem, and Olayiwola Adeola
An investigation into the influence of phytates on the
absorption of amino acids (lysine, glutamate and leucine) and glucose from the intestinal lumen of 3-week-old chickens was carried out. Birds were anaesthetised and the intestines exteriorised. Uptake of 5 mM of each nutrient over a 4-min period was measured in the presence of four phytate concentrations (0, 50, 250 and 500 mM). Five birds were used for each nutrient at each concentration of phytate tested. Leucine uptake decreased linearly (P < 0.001) and that of glutamate showed a tendency to decrease (P = 0.055) as the phytate concentration increased. Absorption of lysine and glucose were unaffected by the presence of phytate. In conclusion, phytate in the small intestinal lumen exerted a depressive effect on the absorption of specific free amino acids from the lumen. Its depressive effect was greatest for leucine followed by glutamate, and phytate had little effect on the absorption of lysine.
at a temperature of 298,15 K.
Aminobutyric acid (Aba), valine (Val), leucine (Leu), isoleucine (Ile) and l -α-cysteine (Cys) (all mass fraction purity > 0.99, Fluka) were crystallized with aqueous ethanol
Uno, T., Furihata, T., Abe, H., Yoshida, R., Shinozaki, K. (2000) Arabidopsis basic leucine zipper transcription factors involved in an abscisic acid-dependent signal transduction pathway under drought and high-salinity conditions. Proc. Natl. Acad
Authors:K. Berisha, H. Bytyçi, Zs. Mednyánszky, E. Kiss, and L. Simon-Sarkadi
Busha milk were glutamic acid (15.19–24.54%), proline (7.45–14.04%), leucine (9.37–13.00%), aspartic acid (6.50–10.59%), lysine (6.97–9.56%), and valine (5.50–6.88%), while the minor ones were cysteine (0–0.87%) and methionine (0.75–2.31%). The main
Authors:R. Tokay, B. Nordén, J. Liljenzin, and S. Andersson
14C labelled solid D- and L-leucine decomposes with significantly different rates by auto-radiolysis. The -decarboxylation ratio (103xCO2%)D/(103xCO2%)L was found to be (2.3±0.2)/(1.2±0.2)= 1.9±0.5 for samples kept in evacuated tubes at room temperature for 1 year /sp. activity: 0.9 MBq g–1; -dose: 224 Gy/. EPR indicates a 10% higher radical concentration in the stored solid D-leucine samples than in L-leucine. The relevance of these results to the question of origin of optical onehandedness in life, is discussed.