|
|
Recyclation and Transformation of Homocysteine as a Part of Detoxication Processes in the Cell
Přistoupilová, K. ; Přistoupil, T. ; Šenholdová, Z. ; Navrátil, Tomáš ; Heyrovský, Michael
The presented metabolic pathways explain how the transformation of homocysteine affects the detoxication processes in the human cell. On the one hand homocysteine is recycled to methionine; on the other hand it is transformed to cysteine. Both pathways are connected by B12 vitamin. Their relation to the thiodiglycolic acid (TDGA), which represents a part of the detoxication processes, is demonstrated on the scheme. The changes in TDGA concentration in urine were found to depend on the changes in redox equilibria (of vitamin B12, folic acid, homocysteine). Key Words: Thiodiglycolic acid, TDGA, vitamin B12, folic acid, metabolic pathways, homocysteine, detoxication.
|
|
|
Změny koncentrace TDGA v moči jako možný marker metabolismu thiosloučenin
Přistoupilová, K. ; Přistoupil, T. I. ; Šenholdová, Z. ; Navrátil, Tomáš ; Heyrovský, Michael ; Fenclová, Z.
The new simple voltammetric method we described recently, proved already to be useful in determining thiodiglycolic acid (TDGA) levels in urine samples of people influenced by some chemicals, victuals and pharmaceuticals. The present pilot study is a continuation of our previous work devoted to test general feasibility of the method. We concentrated upon time dependent quantitative changes of TDGA excretion into urine of selected volunteers. The TDGA level in all morning samples was the highest in comparison with samples collected during the day. The TDGA level was dependent on the health condition of each person involved. However, a further marked increase of TDGA in the morning urine was observed individually, in general when vitamin B12 had been administered in the evening the day before. Vitamin B12 is known to play an important role in the metabolism of one- and two-carbon units, of homocysteine and of sulfhydryls in general. Certain differences in excretion course of TDGA.
|
|
| |
|
|
Anodic Stripping Voltammetry on Silver Composite Electrodes
Kopanica, M. ; Šebková, Světlana ; Navrátil, Tomáš
The influences of presence of various cations (Cd, Cu, Bi, Tl) and anions (chlorides) on the anodic stripping voltammetric determination of lead on silver composite electrodes were studied. It was found that the effect of underpotential deposition at these electrodes differs from that one produced by metallic silver electrode. Their use enables the direct determination in water samples without elimination of the presence of surface-active substances or of dissolved oxygen (LOD about 3 ug L-1).
|
|
| |
|
| |
|
|
Phytochelatins as Cadmium and Zinc Ligands in Study Using Voltammetric Methods
Šestáková, Ivana ; Navrátil, Tomáš
Complexation of synthetically prepared phytochelatin PC3 was studied using differential pulse voltammetry on HMDE. This method allows to measure reduction peak of mercury compound of original peptide simultaneously with the reduction peaks of formed cadmium or zinc complexes. Elimination voltammetry with linear scan was used at selected stoichiometric ratio to characterise diffusion current of complexes formed. Substantial differences were found between Cd and Zn complexes, both in formation and behaviour.
|
guest ::
